1
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Korosec CS, Wahl LM, Heffernan JM. Within-host evolution of SARS-CoV-2: how often are de novo mutations transmitted from symptomatic infections? Virus Evol 2024; 10:veae006. [PMID: 38425472 PMCID: PMC10904108 DOI: 10.1093/ve/veae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/20/2023] [Accepted: 01/12/2024] [Indexed: 03/02/2024] Open
Abstract
Despite a relatively low mutation rate, the large number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections has allowed for substantial genetic change, leading to a multitude of emerging variants. Using a recently determined mutation rate (per site replication), as well as within-host parameter estimates for symptomatic SARS-CoV-2 infection, we apply a stochastic transmission-bottleneck model to describe the survival probability of de novo SARS-CoV-2 mutations as a function of bottleneck size and selection coefficient. For narrow bottlenecks, we find that mutations affecting per-target-cell attachment rate (with phenotypes associated with fusogenicity and ACE2 binding) have similar transmission probabilities to mutations affecting viral load clearance (with phenotypes associated with humoral evasion). We further find that mutations affecting the eclipse rate (with phenotypes associated with reorganization of cellular metabolic processes and synthesis of viral budding precursor material) are highly favoured relative to all other traits examined. We find that mutations leading to reduced removal rates of infected cells (with phenotypes associated with innate immune evasion) have limited transmission advantage relative to mutations leading to humoral evasion. Predicted transmission probabilities, however, for mutations affecting innate immune evasion are more consistent with the range of clinically estimated household transmission probabilities for de novo mutations. This result suggests that although mutations affecting humoral evasion are more easily transmitted when they occur, mutations affecting innate immune evasion may occur more readily. We examine our predictions in the context of a number of previously characterized mutations in circulating strains of SARS-CoV-2. Our work offers both a null model for SARS-CoV-2 mutation rates and predicts which aspects of viral life history are most likely to successfully evolve, despite low mutation rates and repeated transmission bottlenecks.
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Affiliation(s)
- Chapin S Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON M3J 1P3, Canada
| | - Lindi M Wahl
- Applied Mathematics, Western University, 1151 Richmond St, London, ON N6A 5B7, Canada
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON M3J 1P3, Canada
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2
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Akanteva A, Dick DW, Amiraslani S, Heffernan JM. Canadian Covid-19 pandemic public health mitigation measures at the province level. Sci Data 2023; 10:882. [PMID: 38066033 PMCID: PMC10709578 DOI: 10.1038/s41597-023-02759-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
The Covid-19 pandemic has prompted governments across the world to enforce a range of public health interventions. We introduce the Covid-19 Policy Response Canadian tracker (CPRCT) database that tracks and records implemented public health measures in every province and territory in Canada. The implementations are recorded on a four-level ordinal scale (0-3) for three domains, (Schools, Work, and Other), capturing differences in degree of response. The data-set allows the exploration of the effects of public health mitigation on the spread of Covid-19, as well as provides a near-real-time record in an accessible format that is useful for a diverse range of modeling and research questions.
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Affiliation(s)
- Anna Akanteva
- Modelling Infection & Immunity Lab, Centre for Disease Modelling, Mathematics & Statistics, York University, 4700 Keele Street, Toronto, M3J 1P3, Ontario, Canada
| | - David W Dick
- Modelling Infection & Immunity Lab, Centre for Disease Modelling, Mathematics & Statistics, York University, 4700 Keele Street, Toronto, M3J 1P3, Ontario, Canada.
| | - Shirin Amiraslani
- Modelling Infection & Immunity Lab, Centre for Disease Modelling, Mathematics & Statistics, York University, 4700 Keele Street, Toronto, M3J 1P3, Ontario, Canada
| | - Jane M Heffernan
- Modelling Infection & Immunity Lab, Centre for Disease Modelling, Mathematics & Statistics, York University, 4700 Keele Street, Toronto, M3J 1P3, Ontario, Canada.
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3
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Bolton KJ, McCaw JM, Dafilis MP, McVernon J, Heffernan JM. Seasonality as a driver of pH1N12009 influenza vaccination campaign impact. Epidemics 2023; 45:100730. [PMID: 38056164 DOI: 10.1016/j.epidem.2023.100730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 07/18/2023] [Accepted: 11/16/2023] [Indexed: 12/08/2023] Open
Abstract
Although the most recent respiratory virus pandemic was triggered by a Coronavirus, sustained and elevated prevalence of highly pathogenic avian influenza viruses able to infect mammalian hosts highlight the continued threat of pandemics of influenza A virus (IAV) to global health. Retrospective analysis of pandemic outcomes, including comparative investigation of intervention efficacy in different regions, provide important contributions to the evidence base for future pandemic planning. The swine-origin IAV pandemic of 2009 exhibited regional variation in onset, infection dynamics and annual infection attack rates (IARs). For example, the UK experienced three severe peaks of infection over two influenza seasons, whilst Australia experienced a single severe wave. We adopt a seasonally forced 2-subtype model for the transmission of pH1N12009 and seasonal H3N2 to examine the role vaccination campaigns may play in explaining differences in pandemic trajectories in temperate regions. Our model differentiates between the nature of vaccine- and infection-acquired immunity. In particular, we assume that immunity triggered by infection elicits heterologous cross-protection against viral shedding in addition to long-lasting neutralising antibody, whereas vaccination induces imperfect reduction in susceptibility. We employ an Approximate Bayesian Computation (ABC) framework to calibrate the model using data for pH1N12009 seroprevalence, relative subtype dominance, and annual IARs for Australia and the UK. Heterologous cross-protection substantially suppressed the pandemic IAR over the posterior, with the strength of protection against onward transmission inversely correlated with the initial reproduction number. We show that IAV pandemic timing relative to the usual seasonal influenza cycle influenced the size of the initial waves of pH1N12009 in temperate regions and the impact of vaccination campaigns.
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Affiliation(s)
- Kirsty J Bolton
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - James M McCaw
- School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Australia
| | - Mathew P Dafilis
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Australia
| | - Jodie McVernon
- Peter Doherty Institute for Infection and Immunity, The Royal Melbourne Hospital and The University of Melbourne, Parkville, Australia
| | - Jane M Heffernan
- Centre for Disease Modelling, Mathematics & Statistics, York University, Canada
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4
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Molla J, Farhang-Sardroodi S, Moyles IR, Heffernan JM. Pharmaceutical and non-pharmaceutical interventions for controlling the COVID-19 pandemic. R Soc Open Sci 2023; 10:230621. [PMID: 38126062 PMCID: PMC10731327 DOI: 10.1098/rsos.230621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023]
Abstract
Disease spread can be affected by pharmaceutical interventions (such as vaccination) and non-pharmaceutical interventions (such as physical distancing, mask-wearing and contact tracing). Understanding the relationship between disease dynamics and human behaviour is a significant factor to controlling infections. In this work, we propose a compartmental epidemiological model for studying how the infection dynamics of COVID-19 evolves for people with different levels of social distancing, natural immunity and vaccine-induced immunity. Our model recreates the transmission dynamics of COVID-19 in Ontario up to December 2021. Our results indicate that people change their behaviour based on the disease dynamics and mitigation measures. Specifically, they adopt more protective behaviour when mandated social distancing measures are in effect, typically concurrent with a high number of infections. They reduce protective behaviour when vaccination coverage is high or when mandated contact reduction measures are relaxed, typically concurrent with a reduction of infections. We demonstrate that waning of infection and vaccine-induced immunity are important for reproducing disease transmission in autumn 2021.
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Affiliation(s)
- Jeta Molla
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, Ontario, Canada
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, Ontario, Canada
| | - Suzan Farhang-Sardroodi
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, Ontario, Canada
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, Ontario, Canada
- Department of Mathematics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Iain R. Moyles
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, Ontario, Canada
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, Ontario, Canada
| | - Jane M. Heffernan
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, Ontario, Canada
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, Ontario, Canada
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5
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Matveev VA, Mihelic EZ, Benko E, Budylowski P, Grocott S, Lee T, Korosec CS, Colwill K, Stephenson H, Law R, Ward LA, Sheikh-Mohamed S, Mailhot G, Delgado-Brand M, Pasculescu A, Wang JH, Qi F, Tursun T, Kardava L, Chau S, Samaan P, Imran A, Copertino DC, Chao G, Choi Y, Reinhard RJ, Kaul R, Heffernan JM, Jones RB, Chun TW, Moir S, Singer J, Gommerman J, Gingras AC, Kovacs C, Ostrowski M. Immunogenicity of COVID-19 vaccines and their effect on HIV reservoir in older people with HIV. iScience 2023; 26:107915. [PMID: 37790281 PMCID: PMC10542941 DOI: 10.1016/j.isci.2023.107915] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/31/2023] [Accepted: 09/12/2023] [Indexed: 10/05/2023] Open
Abstract
Older individuals and people with HIV (PWH) were prioritized for COVID-19 vaccination, yet comprehensive studies of the immunogenicity of these vaccines and their effects on HIV reservoirs are not available. Our study on 68 PWH and 23 HIV-negative participants aged 55 and older post-three vaccine doses showed equally strong anti-spike IgG responses in serum and saliva through week 48 from baseline, while PWH salivary IgA responses were low. PWH had diminished live-virus neutralization responses after two vaccine doses, which were 'rescued' post-booster. Spike-specific T cell immunity was enhanced in PWH with normal CD4+ T cell count, suggesting Th1 imprinting. The frequency of detectable HIV viremia increased post-vaccination, but vaccines did not affect the size of the HIV reservoir in most PWH, except those with low-level viremia. Thus, older PWH require three doses of COVID-19 vaccine for maximum protection, while individuals with unsuppressed viremia should be monitored for adverse reactions from HIV reservoirs.
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Affiliation(s)
- Vitaliy A. Matveev
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Erik Z. Mihelic
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Erika Benko
- Maple Leaf Medical Clinic, Toronto ON M5G 1K2, Canada
| | - Patrick Budylowski
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
- Institute of Medical Science, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Sebastian Grocott
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
- Department of Microbiology and Immunology, McGill University, Montreal QC H3A 2B4, Canada
| | - Terry Lee
- CIHR Canadian HIV Trials Network (CTN), Vancouver BC V6Z 1Y6, Canada
- Centre for Health Evaluation and Outcome Sciences (CHÉOS), Vancouver BC V6Z IY6, Canada
| | - Chapin S. Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics Department, York University, Toronto ON M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics Department, York University, Toronto ON M3J 1P3, Canada
| | - Karen Colwill
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
| | - Henry Stephenson
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
- Department of Bioengineering, McGill University, Montreal QC H3A 0E9, Canada
| | - Ryan Law
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Lesley A. Ward
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
| | | | - Geneviève Mailhot
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
| | | | - Adrian Pasculescu
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
| | - Jenny H. Wang
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
| | - Freda Qi
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
| | - Tulunay Tursun
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
| | - Lela Kardava
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Serena Chau
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Philip Samaan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Annam Imran
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Dennis C. Copertino
- Infectious Diseases, Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Gary Chao
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Yoojin Choi
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Robert J. Reinhard
- Independent Public/Global Health Consultant, San Francisco, CA 94114, USA
| | - Rupert Kaul
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics Department, York University, Toronto ON M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics Department, York University, Toronto ON M3J 1P3, Canada
| | - R. Brad Jones
- Infectious Diseases, Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Department of Medicine, Weill Cornell Medical College, New York, NY 10021, USA
| | - Tae-Wook Chun
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Susan Moir
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joel Singer
- CIHR Canadian HIV Trials Network (CTN), Vancouver BC V6Z 1Y6, Canada
- Centre for Health Evaluation and Outcome Sciences (CHÉOS), Vancouver BC V6Z IY6, Canada
- School of Population and Public Health, University of British Columbia, Vancouver BC V6T 1Z3, Canada
| | - Jennifer Gommerman
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Colin Kovacs
- Maple Leaf Medical Clinic, Toronto ON M5G 1K2, Canada
- Department of Internal Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Mario Ostrowski
- Department of Medicine, University of Toronto, Toronto ON M5S 1A8, Canada
- Department of Immunology, University of Toronto, Toronto ON M5S 1A8, Canada
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health, Toronto ON M5B 1W8, Canada
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6
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Matveev VA, Mihelic EZ, Benko E, Budylowski P, Grocott S, Lee T, Korosec CS, Colwill K, Stephenson H, Law R, Ward LA, Sheikh-Mohamed S, Mailhot G, Delgado-Brand M, Pasculescu A, Wang JH, Qi F, Tursun T, Kardava L, Chau S, Samaan P, Imran A, Copertino DC, Chao G, Choi Y, Reinhard RJ, Kaul R, Heffernan JM, Jones RB, Chun TW, Moir S, Singer J, Gommerman J, Gingras AC, Kovacs C, Ostrowski M. Immunogenicity of COVID-19 vaccines and their effect on the HIV reservoir in older people with HIV. bioRxiv 2023:2023.06.14.544834. [PMID: 37502977 PMCID: PMC10370192 DOI: 10.1101/2023.06.14.544834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Older individuals and people with HIV (PWH) were prioritized for COVID-19 vaccination, yet comprehensive studies of the immunogenicity of these vaccines and their effects on HIV reservoirs are not available. We followed 68 PWH aged 55 and older and 23 age-matched HIV-negative individuals for 48 weeks from the first vaccine dose, after the total of three doses. All PWH were on antiretroviral therapy (cART) and had different immune status, including immune responders (IR), immune non-responders (INR), and PWH with low-level viremia (LLV). We measured total and neutralizing Ab responses to SARS-CoV-2 spike and RBD in sera, total anti-spike Abs in saliva, frequency of anti-RBD/NTD B cells, changes in frequency of anti-spike, HIV gag/nef-specific T cells, and HIV reservoirs in peripheral CD4 + T cells. The resulting datasets were used to create a mathematical model for within-host immunization. Various regimens of BNT162b2, mRNA-1273, and ChAdOx1 vaccines elicited equally strong anti-spike IgG responses in PWH and HIV - participants in serum and saliva at all timepoints. These responses had similar kinetics in both cohorts and peaked at 4 weeks post-booster (third dose), while half-lives of plasma IgG also dramatically increased post-booster in both groups. Salivary spike IgA responses were low, especially in INRs. PWH had diminished live virus neutralizing titers after two vaccine doses which were 'rescued' after a booster. Anti-spike T cell immunity was enhanced in IRs even in comparison to HIV - participants, suggesting Th1 imprinting from HIV, while in INRs it was the lowest. Increased frequency of viral 'blips' in PWH were seen post-vaccination, but vaccines did not affect the size of the intact HIV reservoir in CD4 + T cells in most PWH, except in LLVs. Thus, older PWH require three doses of COVID-19 vaccine to maximize neutralizing responses against SARS-CoV-2, although vaccines may increase HIV reservoirs in PWH with persistent viremia.
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Affiliation(s)
| | - Erik Z. Mihelic
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
| | - Erika Benko
- Maple Leaf Medical Clinic, Toronto, ON, Canada
| | - Patrick Budylowski
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Sebastian Grocott
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
- Dept of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Terry Lee
- CIHR Canadian HIV Trials Network (CTN), Vancouver, BC, Canada
- Centre for Health Evaluation and Outcome Sciences (CHÉOS), Vancouver, BC, Canada
| | - Chapin S. Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics Dept, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics Dept, York University, Toronto, ON, Canada
| | - Karen Colwill
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | - Henry Stephenson
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
- Dept of Bioengineering, McGill University, Montreal, QC, Canada
| | - Ryan Law
- Dept of Immunology, University of Toronto, Toronto, ON, Canada
| | - Lesley A. Ward
- Dept of Immunology, University of Toronto, Toronto, ON, Canada
| | | | - Geneviève Mailhot
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | | | - Adrian Pasculescu
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | - Jenny H. Wang
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | - Freda Qi
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | - Tulunay Tursun
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
| | - Lela Kardava
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Serena Chau
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
| | - Philip Samaan
- Dept of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Annam Imran
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
| | - Dennis C. Copertino
- Infectious Diseases, Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Gary Chao
- Dept of Immunology, University of Toronto, Toronto, ON, Canada
| | - Yoojin Choi
- Dept of Immunology, University of Toronto, Toronto, ON, Canada
| | | | - Rupert Kaul
- Dept of Immunology, University of Toronto, Toronto, ON, Canada
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics Dept, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics Dept, York University, Toronto, ON, Canada
| | - R. Brad Jones
- Infectious Diseases, Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
- Dept of Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Tae-Wook Chun
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Susan Moir
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Joel Singer
- CIHR Canadian HIV Trials Network (CTN), Vancouver, BC, Canada
- Centre for Health Evaluation and Outcome Sciences (CHÉOS), Vancouver, BC, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | | | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, ON, Canada
- Dept of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Colin Kovacs
- Maple Leaf Medical Clinic, Toronto, ON, Canada
- Dept of Internal Medicine, University of Toronto, Toronto, ON, Canada
- Senior authors
| | - Mario Ostrowski
- Dept of Medicine, University of Toronto, Toronto, ON, Canada
- Dept of Immunology, University of Toronto, Toronto, ON, Canada
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Unity Health, Toronto, ON, Canada
- Senior authors
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7
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Banuet-Martinez M, Yang Y, Jafari B, Kaur A, Butt ZA, Chen HH, Yanushkevich S, Moyles IR, Heffernan JM, Korosec CS. Monkeypox: a review of epidemiological modelling studies and how modelling has led to mechanistic insight. Epidemiol Infect 2023; 151:e121. [PMID: 37218612 PMCID: PMC10468816 DOI: 10.1017/s0950268823000791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 05/24/2023] Open
Abstract
Human monkeypox (mpox) virus is a viral zoonosis that belongs to the Orthopoxvirus genus of the Poxviridae family, which presents with similar symptoms as those seen in human smallpox patients. Mpox is an increasing concern globally, with over 80,000 cases in non-endemic countries as of December 2022. In this review, we provide a brief history and ecology of mpox, its basic virology, and the key differences in mpox viral fitness traits before and after 2022. We summarize and critique current knowledge from epidemiological mathematical models, within-host models, and between-host transmission models using the One Health approach, where we distinguish between models that focus on immunity from vaccination, geography, climatic variables, as well as animal models. We report various epidemiological parameters, such as the reproduction number, R0, in a condensed format to facilitate comparison between studies. We focus on how mathematical modelling studies have led to novel mechanistic insight into mpox transmission and pathogenesis. As mpox is predicted to lead to further infection peaks in many historically non-endemic countries, mathematical modelling studies of mpox can provide rapid actionable insights into viral dynamics to guide public health measures and mitigation strategies.
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Affiliation(s)
- Marina Banuet-Martinez
- Climate Change and Global Health Research Group, School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Yang Yang
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Behnaz Jafari
- Mathematics and Statistics Department, Faculty of Science, University of Calgary, Calgary, AB, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - Avneet Kaur
- Irving K. Barber School of Arts and Sciences, Department of Computer Science, Mathematics, Physics and Statistics, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Zahid A. Butt
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Helen H. Chen
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Svetlana Yanushkevich
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - Iain R. Moyles
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Chapin S. Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada
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8
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Korosec CS, Betti MI, Dick DW, Ooi HK, Moyles IR, Wahl LM, Heffernan JM. Multiple cohort study of hospitalized SARS-CoV-2 in-host infection dynamics: Parameter estimates, identifiability, sensitivity and the eclipse phase profile. J Theor Biol 2023; 564:111449. [PMID: 36894132 PMCID: PMC9990894 DOI: 10.1016/j.jtbi.2023.111449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 02/09/2023] [Accepted: 02/22/2023] [Indexed: 03/09/2023]
Abstract
Within-host SARS-CoV-2 modelling studies have been published throughout the COVID-19 pandemic. These studies contain highly variable numbers of individuals and capture varying timescales of pathogen dynamics; some studies capture the time of disease onset, the peak viral load and subsequent heterogeneity in clearance dynamics across individuals, while others capture late-time post-peak dynamics. In this study, we curate multiple previously published SARS-CoV-2 viral load data sets, fit these data with a consistent modelling approach, and estimate the variability of in-host parameters including the basic reproduction number, R0, as well as the best-fit eclipse phase profile. We find that fitted dynamics can be highly variable across data sets, and highly variable within data sets, particularly when key components of the dynamic trajectories (e.g. peak viral load) are not represented in the data. Further, we investigated the role of the eclipse phase time distribution in fitting SARS-CoV-2 viral load data. By varying the shape parameter of an Erlang distribution, we demonstrate that models with either no eclipse phase, or with an exponentially-distributed eclipse phase, offer significantly worse fits to these data, whereas models with less dispersion around the mean eclipse time (shape parameter two or more) offered the best fits to the available data across all data sets used in this work. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".
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Affiliation(s)
- Chapin S Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada; Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada.
| | - Matthew I Betti
- Department of Mathematics and Computer Science, Mount Allison University, 62 York St, Sackville, E4L 1E2, NB, Canada.
| | - David W Dick
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada; Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada.
| | - Hsu Kiang Ooi
- Digital Technologies Research Centre, National Research Council Canada, 222 College Street, Toronto, M5T 3J1, ON, Canada.
| | - Iain R Moyles
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada; Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada.
| | - Lindi M Wahl
- Mathematics, Western University, 1151 Richmond St, London, N6A 5B7, ON, Canada.
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada; Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, M3J 1P3, ON, Canada.
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9
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Moyles IR, Korosec CS, Heffernan JM. Determination of significant immunological timescales from mRNA-LNP-based vaccines in humans. J Math Biol 2023; 86:86. [PMID: 37121986 PMCID: PMC10149047 DOI: 10.1007/s00285-023-01919-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 03/10/2023] [Accepted: 04/07/2023] [Indexed: 05/02/2023]
Abstract
A compartment model for an in-host liquid nanoparticle delivered mRNA vaccine is presented. Through non-dimensionalisation, five timescales are identified that dictate the lifetime of the vaccine in-host: decay of interferon gamma, antibody priming, autocatalytic growth, antibody peak and decay, and interleukin cessation. Through asymptotic analysis we are able to obtain semi-analytical solutions in each of the time regimes which allows us to predict maximal concentrations and better understand parameter dependence in the model. We compare our model to 22 data sets for the BNT162b2 and mRNA-1273 mRNA vaccines demonstrating good agreement. Using our analysis, we estimate the values for each of the five timescales in each data set and predict maximal concentrations of plasma B-cells, antibody, and interleukin. Through our comparison, we do not observe any discernible differences between vaccine candidates and sex. However, we do identify an age dependence, specifically that vaccine activation takes longer and that peak antibody occurs sooner in patients aged 55 and greater.
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Affiliation(s)
- Iain R Moyles
- Department of Mathematics and Statistics, York University, 4700 Keele Street, Toronto, ON, M3J1P3, Canada.
| | - Chapin S Korosec
- Department of Mathematics and Statistics, York University, 4700 Keele Street, Toronto, ON, M3J1P3, Canada
| | - Jane M Heffernan
- Department of Mathematics and Statistics, York University, 4700 Keele Street, Toronto, ON, M3J1P3, Canada
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10
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Betti MI, Abouleish AH, Spofford V, Peddigrew C, Diener A, Heffernan JM. COVID-19 Vaccination and Healthcare Demand. Bull Math Biol 2023; 85:32. [PMID: 36930340 PMCID: PMC10021065 DOI: 10.1007/s11538-023-01130-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/09/2023] [Indexed: 03/18/2023]
Abstract
One of the driving concerns during any epidemic is the strain on the healthcare system. As we have seen many times over the globe with the COVID-19 pandemic, hospitals and ICUs can quickly become overwhelmed by cases. While strict periods of public health mitigation have certainly helped decrease incidence and thus healthcare demand, vaccination is the only clear long-term solution. In this paper, we develop a two-module model to forecast the effects of relaxation of non-pharmaceutical intervention and vaccine uptake on daily incidence, and the cascade effects on healthcare demand. The first module is a simple epidemiological model which incorporates non-pharmaceutical intervention, the relaxation of such measures and vaccination campaigns to predict caseloads into the Fall of 2021. This module is then fed into a healthcare module which can forecast the number of doctor visits, the number of occupied hospital beds, number of occupied ICU beds and any excess demand of these. From this module, we can also estimate the length of stay of individuals in ICU. For model verification and forecasting, we use the four most populous Canadian provinces as a case study.
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Affiliation(s)
- Matthew I Betti
- Mathematics and Computer Science, Mount Allison University, Sackville, NB, Canada
| | | | | | | | | | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada.
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11
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Wang Y, Liu J, Zhang X, Heffernan JM. An HIV stochastic model with cell-to-cell infection, B-cell immune response and distributed delay. J Math Biol 2023; 86:35. [PMID: 36695912 DOI: 10.1007/s00285-022-01863-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 12/07/2022] [Accepted: 12/15/2022] [Indexed: 01/26/2023]
Abstract
In this study, a delayed HIV stochastic model with virus-to-cell infection, cell-to-cell transmission and B-cell immune response is proposed. We first transform the stochastic differential equation with distributed delay into a high-dimensional degenerate stochastic differential equation, and then theoretically analyze the dynamic behaviour of the degenerate model. The unique global solution of the model is given by rigorous analysis. By formulating suitable Lyapunov functions, the existence of the stationary Markov process is obtained if the stochastic B-cell-activated reproduction number is greater than one. We also use the law of large numbers theorem and the spectral radius analysis method to deduce that the virus can be cleared if the stochastic B-cell-inactivated reproduction number is less than one. Through uncertainty and sensitivity analysis, we obtain key parameters that determine the value of the stochastic B-cell-activated reproduction number. Numerically, we examine that low level noise can maintain the number of the virus and B-cell populations at a certain range, while high level noise is helpful for the elimination of the virus. Furthermore, the effect of the cell-to-cell infection on model behaviour, and the influence of the key parameters on the size of the stochastic B-cell-activated reproduction number are also investigated.
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Affiliation(s)
- Yan Wang
- College of Science, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Jun Liu
- College of Science, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Xinhong Zhang
- College of Science, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, M3J 1P3, Canada.
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12
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Korosec CS, Farhang-Sardroodi S, Dick DW, Gholami S, Ghaemi MS, Moyles IR, Craig M, Ooi HK, Heffernan JM. Long-term durability of immune responses to the BNT162b2 and mRNA-1273 vaccines based on dosage, age and sex. Sci Rep 2022; 12:21232. [PMID: 36481777 PMCID: PMC9732004 DOI: 10.1038/s41598-022-25134-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022] Open
Abstract
The lipid nanoparticle (LNP)-formulated mRNA vaccines BNT162b2 and mRNA-1273 are a widely adopted multi vaccination public health strategy to manage the COVID-19 pandemic. Clinical trial data has described the immunogenicity of the vaccine, albeit within a limited study time frame. Here, we use a within-host mathematical model for LNP-formulated mRNA vaccines, informed by available clinical trial data from 2020 to September 2021, to project a longer term understanding of immunity as a function of vaccine type, dosage amount, age, and sex. We estimate that two standard doses of either mRNA-1273 or BNT162b2, with dosage times separated by the company-mandated intervals, results in individuals losing more than 99% humoral immunity relative to peak immunity by 8 months following the second dose. We predict that within an 8 month period following dose two (corresponding to the original CDC time-frame for administration of a third dose), there exists a period of time longer than 1 month where an individual has lost more than 99% humoral immunity relative to peak immunity, regardless of which vaccine was administered. We further find that age has a strong influence in maintaining humoral immunity; by 8 months following dose two we predict that individuals aged 18-55 have a four-fold humoral advantage compared to aged 56-70 and 70+ individuals. We find that sex has little effect on the immune response and long-term IgG counts. Finally, we find that humoral immunity generated from two low doses of mRNA-1273 decays at a substantially slower rate relative to peak immunity gained compared to two standard doses of either mRNA-1273 or BNT162b2. Our predictions highlight the importance of the recommended third booster dose in order to maintain elevated levels of antibodies.
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Affiliation(s)
- Chapin S Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada.
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada.
| | - Suzan Farhang-Sardroodi
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
- Department of Mathematics, University of Manitoba, 186 Dysart Road, Winnipeg, MB, R3T 2N2, Canada
| | - David W Dick
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - Sameneh Gholami
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - Mohammad Sajjad Ghaemi
- Digital Technologies Research Centre, National Research Council Canada, 222 College Street, Toronto, ON, M5T 3J1, Canada
| | - Iain R Moyles
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - Morgan Craig
- Department of Mathematics and Statistics, Université de Montréal & Sainte-Justine University Hospital Research Centre, 3175, ch. Côte Sainte-Catherine, Montréal, QC, H3T 1C5, Canada
| | - Hsu Kiang Ooi
- Digital Technologies Research Centre, National Research Council Canada, 222 College Street, Toronto, ON, M5T 3J1, Canada
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada.
- Centre for Disease Modelling, Mathematics and Statistics, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada.
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13
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Vegvari C, Abbott S, Ball F, Brooks-Pollock E, Challen R, Collyer BS, Dangerfield C, Gog JR, Gostic KM, Heffernan JM, Hollingsworth TD, Isham V, Kenah E, Mollison D, Panovska-Griffiths J, Pellis L, Roberts MG, Scalia Tomba G, Thompson RN, Trapman P. Commentary on the use of the reproduction number R during the COVID-19 pandemic. Stat Methods Med Res 2022; 31:1675-1685. [PMID: 34569883 PMCID: PMC9277711 DOI: 10.1177/09622802211037079] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Since the beginning of the COVID-19 pandemic, the reproduction number [Formula: see text] has become a popular epidemiological metric used to communicate the state of the epidemic. At its most basic, [Formula: see text] is defined as the average number of secondary infections caused by one primary infected individual. [Formula: see text] seems convenient, because the epidemic is expanding if [Formula: see text] and contracting if [Formula: see text]. The magnitude of [Formula: see text] indicates by how much transmission needs to be reduced to control the epidemic. Using [Formula: see text] in a naïve way can cause new problems. The reasons for this are threefold: (1) There is not just one definition of [Formula: see text] but many, and the precise definition of [Formula: see text] affects both its estimated value and how it should be interpreted. (2) Even with a particular clearly defined [Formula: see text], there may be different statistical methods used to estimate its value, and the choice of method will affect the estimate. (3) The availability and type of data used to estimate [Formula: see text] vary, and it is not always clear what data should be included in the estimation. In this review, we discuss when [Formula: see text] is useful, when it may be of use but needs to be interpreted with care, and when it may be an inappropriate indicator of the progress of the epidemic. We also argue that careful definition of [Formula: see text], and the data and methods used to estimate it, can make [Formula: see text] a more useful metric for future management of the epidemic.
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Affiliation(s)
- Carolin Vegvari
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, 4615Imperial College London, London, UK
| | - Sam Abbott
- Center for the Mathematical Modelling of Infectious Diseases, 4906London School of Hygiene & Tropical Medicine, UK
| | - Frank Ball
- School of Mathematical Sciences, 6123University of Nottingham, UK
| | - Ellen Brooks-Pollock
- Bristol Veterinary School, 1980University of Bristol, UK.,NIHR Health Protection Research Unit in Behavioural Science and Evaluation at the University of Bristol, UK
| | - Robert Challen
- EPSRC Centre for Predictive Modelling in Healthcare, 3286University of Exeter, UK.,Somerset NHS Foundation Trust, UK
| | - Benjamin S Collyer
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, 4615Imperial College London, London, UK
| | | | - Julia R Gog
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK
| | - Katelyn M Gostic
- Department of Ecology and Evolution, 2462University of Chicago, USA
| | - Jane M Heffernan
- Centre for Disease Modelling, Mathematics & Statistics, 7991York University, Canada.,COVID Modelling Task-Force, The Fields Institute, Canada
| | - T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, 6396University of Oxford, UK
| | - Valerie Isham
- Department of Statistical Science, 4919University College London, UK
| | - Eben Kenah
- Division of Biostatistics, College of Public Health, 2647The Ohio State University, USA
| | - Denis Mollison
- Department of Actuarial Mathematics and Statistics, Heriot-Watt University, UK
| | - Jasmina Panovska-Griffiths
- The Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.,Wolfson Centre for Mathematical Biology, Mathematical Institute and The Queen's College, University of Oxford, Oxford, UK
| | - Lorenzo Pellis
- Department of Mathematics, 5292The University of Manchester, UK.,The Alan Turing Institute, UK
| | - Michael G Roberts
- School of Natural and Computational Sciences and New Zealand Institute for Advanced Study, Massey University, New Zealand
| | | | - Robin N Thompson
- Mathematics Institute, 2707University of Warwick, Coventry, UK.,Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, 2707University of Warwick, Coventry, UK
| | - Pieter Trapman
- Department of Mathematics, 7675Stockholm University, Sweden
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14
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Childs L, Dick DW, Feng Z, Heffernan JM, Li J, Röst G. Modeling waning and boosting of COVID-19 in Canada with vaccination. Epidemics 2022; 39:100583. [PMID: 35665614 PMCID: PMC9132433 DOI: 10.1016/j.epidem.2022.100583] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 12/04/2021] [Accepted: 05/16/2022] [Indexed: 12/13/2022] Open
Abstract
SARS-CoV-2, the causative agent of COVID-19, has caused devastating health and economic impacts around the globe since its appearance in late 2019. The advent of effective vaccines leads to open questions on how best to vaccinate the population. To address such questions, we developed a model of COVID-19 infection by age that includes the waning and boosting of immunity against SARS-CoV-2 in the context of infection and vaccination. The model also accounts for changes to infectivity of the virus, such as public health mitigation protocols over time, increases in the transmissibility of variants of concern, changes in compliance to mask wearing and social distancing, and changes in testing rates. The model is employed to study public health mitigation and vaccination of the COVID-19 epidemic in Canada, including different vaccination programs (rollout by age), and delays between doses in a two-dose vaccine. We find that the decision to delay the second dose of vaccine is appropriate in the Canadian context. We also find that the benefits of a COVID-19 vaccination program in terms of reductions in infections is increased if vaccination of 15–19 year olds are included in the vaccine rollout.
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Affiliation(s)
- Lauren Childs
- Mathematics, Center for Emerging and Zoonotic Pathogens, Virginia Tech, Blacksburg, VA, USA
| | - David W Dick
- Mathematics and Statistics, Centre for Disease Modelling, York University, Toronto, Canada
| | - Zhilan Feng
- Mathematics, Purdue University, West Lafayette IN, USA; National Science Foundation, Alexandria, VA, USA
| | - Jane M Heffernan
- Mathematics and Statistics, Centre for Disease Modelling, York University, Toronto, Canada.
| | - Jing Li
- Mathematics, California State University, Northridge, CA, USA
| | - Gergely Röst
- Mathematics, University of Szeged, Szeged, Hungary
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15
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Farhang-Sardroodi S, Ghaemi MS, Craig M, Ooi HK, Heffernan JM. A machine learning approach to differentiate between COVID-19 and influenza infection using synthetic infection and immune response data. Math Biosci Eng 2022; 19:5813-5831. [PMID: 35603380 DOI: 10.3934/mbe.2022272] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Data analysis is widely used to generate new insights into human disease mechanisms and provide better treatment methods. In this work, we used the mechanistic models of viral infection to generate synthetic data of influenza and COVID-19 patients. We then developed and validated a supervised machine learning model that can distinguish between the two infections. Influenza and COVID-19 are contagious respiratory illnesses that are caused by different pathogenic viruses but appeared with similar initial presentations. While having the same primary signs COVID-19 can produce more severe symptoms, illnesses, and higher mortality. The predictive model performance was externally evaluated by the ROC AUC metric (area under the receiver operating characteristic curve) on 100 virtual patients from each cohort and was able to achieve at least AUC = 91% using our multiclass classifier. The current investigation highlighted the ability of machine learning models to accurately identify two different diseases based on major components of viral infection and immune response. The model predicted a dominant role for viral load and productively infected cells through the feature selection process.
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Affiliation(s)
- Suzan Farhang-Sardroodi
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, Canada
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, Canada
| | - Mohammad Sajjad Ghaemi
- Digital Technologies Research Centre, National Research Council Canada, Toronto, ON, Canada
| | - Morgan Craig
- Sainte-Justine University Hospital Research Centre and Department of Mathematics and Statistics, Université de Montréal, Montreal, Quebec, Canada
| | - Hsu Kiang Ooi
- Digital Technologies Research Centre, National Research Council Canada, Toronto, ON, Canada
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, Canada
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, Canada
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16
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Dick DW, Childs L, Feng Z, Li J, Röst G, Buckeridge DL, Ogden NH, Heffernan JM. COVID-19 Seroprevalence in Canada Modelling Waning and Boosting COVID-19 Immunity in Canada a Canadian Immunization Research Network Study. Vaccines (Basel) 2021; 10:17. [PMID: 35062678 PMCID: PMC8779812 DOI: 10.3390/vaccines10010017] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/23/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022] Open
Abstract
COVID-19 seroprevalence changes over time, with infection, vaccination, and waning immunity. Seroprevalence estimates are needed to determine when increased COVID-19 vaccination coverage is needed, and when booster doses should be considered, to reduce the spread and disease severity of COVID-19 infection. We use an age-structured model including infection, vaccination and waning immunity to estimate the distribution of immunity to COVID-19 in the Canadian population. This is the first mathematical model to do so. We estimate that 60-80% of the Canadian population has some immunity to COVID-19 by late Summer 2021, depending on specific characteristics of the vaccine and the waning rate of immunity. Models results indicate that increased vaccination uptake in age groups 12-29, and booster doses in age group 50+ are needed to reduce the severity COVID-19 Fall 2021 resurgence.
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Affiliation(s)
- David W. Dick
- Mathematics and Statistics, Centre for Disease Modelling, York University, Toronto, ON M3J 1P3, Canada;
| | - Lauren Childs
- Department of Mathematics, Virginia Tech, Blacksburg, VA 24061, USA;
| | - Zhilan Feng
- Department of Mathematics, Purdue University, West Lafayette, IN 46202, USA;
- National Science Foundation, Alexandria, VA 22314, USA
| | - Jing Li
- Department of Mathematics, California State University, Northridge, CA 91330, USA;
| | - Gergely Röst
- Department of Mathematics, University of Szeged, 6720 Szeged, Hungary;
| | - David L. Buckeridge
- Epidemiology and Biostatistics, School of Population and Global Health, McGill University, Montreal, QC H3A 0G4, Canada;
| | - Nick H. Ogden
- National Microbiology Laboratory, Public Health Risk Sciences Division, Public Health Agency of Canada, St. Hyacinthe, QC J2S 2M2, Canada;
| | - Jane M. Heffernan
- Mathematics and Statistics, Centre for Disease Modelling, York University, Toronto, ON M3J 1P3, Canada;
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17
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Farhang-Sardroodi S, Korosec CS, Gholami S, Craig M, Moyles IR, Ghaemi MS, Ooi HK, Heffernan JM. Analysis of Host Immunological Response of Adenovirus-Based COVID-19 Vaccines. Vaccines (Basel) 2021; 9:861. [PMID: 34451985 PMCID: PMC8402548 DOI: 10.3390/vaccines9080861] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/22/2021] [Accepted: 07/27/2021] [Indexed: 12/18/2022] Open
Abstract
During the SARS-CoV-2 global pandemic, several vaccines, including mRNA and adenovirus vector approaches, have received emergency or full approval. However, supply chain logistics have hampered global vaccine delivery, which is impacting mass vaccination strategies. Recent studies have identified different strategies for vaccine dose administration so that supply constraints issues are diminished. These include increasing the time between consecutive doses in a two-dose vaccine regimen and reducing the dosage of the second dose. We consider both of these strategies in a mathematical modeling study of a non-replicating viral vector adenovirus vaccine in this work. We investigate the impact of different prime-boost strategies by quantifying their effects on immunological outcomes based on simple system of ordinary differential equations. The boost dose is administered either at a standard dose (SD) of 1000 or at a low dose (LD) of 500 or 250 vaccine particles. Results show dose-dependent immune response activity. Our model predictions show that by stretching the prime-boost interval to 18 or 20, in an SD/SD or SD/LD regimen, the minimum promoted antibody (Nab) response will be comparable with the neutralizing antibody level measured in COVID-19 recovered patients. Results also show that the minimum stimulated antibody in SD/SD regimen is identical with the high level observed in clinical trial data. We conclude that an SD/LD regimen may provide protective capacity, which will allow for conservation of vaccine doses.
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Affiliation(s)
- Suzan Farhang-Sardroodi
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada; (C.S.K.); (S.G.)
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada;
| | - Chapin S. Korosec
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada; (C.S.K.); (S.G.)
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada;
| | - Samaneh Gholami
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada; (C.S.K.); (S.G.)
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada;
| | - Morgan Craig
- Sainte-Justine University Hospital Research Centre and Department of Mathematics and Statistics, Université de Montréal, Montreal, QC H3T 1J4, Canada;
| | - Iain R. Moyles
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada;
| | - Mohammad Sajjad Ghaemi
- Digital Technologies Research Centre, National Research Council Canada, Toronto, ON C1A 4P3, Canada; (M.S.G.); (H.K.O.)
| | - Hsu Kiang Ooi
- Digital Technologies Research Centre, National Research Council Canada, Toronto, ON C1A 4P3, Canada; (M.S.G.); (H.K.O.)
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada; (C.S.K.); (S.G.)
- Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada;
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18
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Betti M, Bragazzi NL, Heffernan JM, Kong J, Raad A. Integrated vaccination and non-pharmaceutical interventions based strategies in Ontario, Canada, as a case study: a mathematical modelling study. J R Soc Interface 2021. [PMID: 34255985 DOI: 10.1101/2021.01.06.21249272] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023] Open
Abstract
Recently, two coronavirus disease 2019 (COVID-19) vaccine products have been authorized in Canada. It is of crucial importance to model an integrated/combined package of non-pharmaceutical (physical/social distancing) and pharmaceutical (immunization) public health control measures. A modified epidemiological, compartmental SIR model was used and fit to the cumulative COVID-19 case data for the province of Ontario, Canada, from 8 September 2020 to 8 December 2020. Different vaccine roll-out strategies were simulated until 75% of the population was vaccinated, including a no-vaccination scenario. We compete these vaccination strategies with relaxation of non-pharmaceutical interventions. Non-pharmaceutical interventions were supposed to remain enforced and began to be relaxed on 31 January, 31 March or 1 May 2021. Based on projections from the data and long-term extrapolation of scenarios, relaxing the public health measures implemented by re-opening too early would cause any benefits of vaccination to be lost by increasing case numbers, increasing the effective reproduction number above 1 and thus increasing the risk of localized outbreaks. If relaxation is, instead, delayed and 75% of the Ontarian population gets vaccinated by the end of the year, re-opening can occur with very little risk. Relaxing non-pharmaceutical interventions by re-opening and vaccine deployment is a careful balancing act. Our combination of model projections from data and simulation of different strategies and scenarios, can equip local public health decision- and policy-makers with projections concerning the COVID-19 epidemiological trend, helping them in the decision-making process.
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Affiliation(s)
- Matthew Betti
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - Nicola Luigi Bragazzi
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
| | - Jane M Heffernan
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Centre for Disease Modeling, York University, Toronto, Ontario, Canada M3J 1P3
| | - Jude Kong
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Centre for Disease Modeling, York University, Toronto, Ontario, Canada M3J 1P3
| | - Angie Raad
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Centre for Disease Modeling, York University, Toronto, Ontario, Canada M3J 1P3
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19
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Betti M, Bragazzi NL, Heffernan JM, Kong J, Raad A. Integrated vaccination and non-pharmaceutical interventions based strategies in Ontario, Canada, as a case study: a mathematical modelling study. J R Soc Interface 2021; 18:20210009. [PMID: 34255985 PMCID: PMC8277469 DOI: 10.1098/rsif.2021.0009] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 06/15/2021] [Indexed: 12/18/2022] Open
Abstract
Recently, two coronavirus disease 2019 (COVID-19) vaccine products have been authorized in Canada. It is of crucial importance to model an integrated/combined package of non-pharmaceutical (physical/social distancing) and pharmaceutical (immunization) public health control measures. A modified epidemiological, compartmental SIR model was used and fit to the cumulative COVID-19 case data for the province of Ontario, Canada, from 8 September 2020 to 8 December 2020. Different vaccine roll-out strategies were simulated until 75% of the population was vaccinated, including a no-vaccination scenario. We compete these vaccination strategies with relaxation of non-pharmaceutical interventions. Non-pharmaceutical interventions were supposed to remain enforced and began to be relaxed on 31 January, 31 March or 1 May 2021. Based on projections from the data and long-term extrapolation of scenarios, relaxing the public health measures implemented by re-opening too early would cause any benefits of vaccination to be lost by increasing case numbers, increasing the effective reproduction number above 1 and thus increasing the risk of localized outbreaks. If relaxation is, instead, delayed and 75% of the Ontarian population gets vaccinated by the end of the year, re-opening can occur with very little risk. Relaxing non-pharmaceutical interventions by re-opening and vaccine deployment is a careful balancing act. Our combination of model projections from data and simulation of different strategies and scenarios, can equip local public health decision- and policy-makers with projections concerning the COVID-19 epidemiological trend, helping them in the decision-making process.
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Affiliation(s)
- Matthew Betti
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - Nicola Luigi Bragazzi
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
| | - Jane M. Heffernan
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Centre for Disease Modeling, York University, Toronto, Ontario, Canada M3J 1P3
| | - Jude Kong
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Centre for Disease Modeling, York University, Toronto, Ontario, Canada M3J 1P3
| | - Angie Raad
- Department of Mathematics and Statistics, Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario, Canada M3J 1P3
- Centre for Disease Modeling, York University, Toronto, Ontario, Canada M3J 1P3
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20
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Bolotin S, Hughes SL, Gul N, Khan S, Rota PA, Severini A, Hahné S, Tricco A, Moss WJ, Orenstein W, Turner N, Durrheim D, Heffernan JM, Crowcroft N. What Is the Evidence to Support a Correlate of Protection for Measles? A Systematic Review. J Infect Dis 2021; 221:1576-1583. [PMID: 31674648 DOI: 10.1093/infdis/jiz380] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/22/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Many studies assume that the serologic correlate of protection from measles disease is 120 mIU/mL. We systematically reviewed the literature to examine the evidence supporting this correlate of protection. METHODS We searched peer-reviewed and gray literature for articles reporting a measles correlate of protection. We excluded studies focusing on special populations, infants aged <9 months, and those using animal models or nonstandard vaccines or administration routes. We extracted and synthesized data from full-text articles that met inclusion criteria. RESULTS We screened 14 778 articles and included 5 studies in our review. The studies reported either preexposure antibody concentrations of individuals along with a description of symptoms postexposure, or the proportion of measles cases that had preexposure antibody concentrations above a threshold of immunity specified by the authors. Some studies also described secondary antibody responses upon exposure. The variation in laboratory methods between studies made comparisons difficult. Some of the studies that assumed 120 mIU/mL as a correlate of protection identified symptomatic individuals with preexposure titers exceeding this threshold. CONCLUSIONS Our findings underscore the scant data upon which the commonly used 120 mIU/mL measles threshold of protection is based, suggesting that further work is required to characterize the measles immunity threshold.
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Affiliation(s)
- Shelly Bolotin
- Public Health Ontario, Toronto, Ontario, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Nazish Gul
- Public Health Ontario, Toronto, Ontario, Canada
| | | | - Paul A Rota
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Alberto Severini
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.,Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Susan Hahné
- National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Andrea Tricco
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.,Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, Ontario, Canada
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Walter Orenstein
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Nikki Turner
- Department of General Practice and Primary Health Care, Faculty of Medicine and Health Science, University of Auckland, Tamaki Campus, Auckland, New Zealand
| | | | - Jane M Heffernan
- Centre for Disease Modelling, Mathematics and Statistics, York University,, Toronto, Ontario, Canada
| | - Natasha Crowcroft
- Public Health Ontario, Toronto, Ontario, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,ICES, Toronto, Ontario, Canada
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21
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McCarthy Z, Xiao Y, Scarabel F, Tang B, Bragazzi NL, Nah K, Heffernan JM, Asgary A, Murty VK, Ogden NH, Wu J. Quantifying the shift in social contact patterns in response to non-pharmaceutical interventions. J Math Ind 2020; 10:28. [PMID: 33282625 PMCID: PMC7707617 DOI: 10.1186/s13362-020-00096-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 11/25/2020] [Indexed: 05/03/2023]
Abstract
Social contact mixing plays a critical role in influencing the transmission routes of infectious diseases. Moreover, quantifying social contact mixing patterns and their variations in a rapidly evolving pandemic intervened by changing public health measures is key for retroactive evaluation and proactive assessment of the effectiveness of different age- and setting-specific interventions. Contact mixing patterns have been used to inform COVID-19 pandemic public health decision-making; but a rigorously justified methodology to identify setting-specific contact mixing patterns and their variations in a rapidly developing pandemic, which can be informed by readily available data, is in great demand and has not yet been established. Here we fill in this critical gap by developing and utilizing a novel methodology, integrating social contact patterns derived from empirical data with a disease transmission model, that enables the usage of age-stratified incidence data to infer age-specific susceptibility, daily contact mixing patterns in workplace, household, school and community settings; and transmission acquired in these settings under different physical distancing measures. We demonstrated the utility of this methodology by performing an analysis of the COVID-19 epidemic in Ontario, Canada. We quantified the age- and setting (household, workplace, community, and school)-specific mixing patterns and their evolution during the escalation of public health interventions in Ontario, Canada. We estimated a reduction in the average individual contact rate from 12.27 to 6.58 contacts per day, with an increase in household contacts, following the implementation of control measures. We also estimated increasing trends by age in both the susceptibility to infection by SARS-CoV-2 and the proportion of symptomatic individuals diagnosed. Inferring the age- and setting-specific social contact mixing and key age-stratified epidemiological parameters, in the presence of evolving control measures, is critical to inform decision- and policy-making for the current COVID-19 pandemic.
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Affiliation(s)
- Zachary McCarthy
- Fields-CQAM Laboratory of Mathematics for Public Health (MfPH), York University, Toronto, Ontario Canada
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario Canada
| | - Yanyu Xiao
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, OH USA
| | - Francesca Scarabel
- Fields-CQAM Laboratory of Mathematics for Public Health (MfPH), York University, Toronto, Ontario Canada
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario Canada
- CDLab—Computational Dynamics Laboratory, Department of Mathematics, Computer Science and Physics, University of Udine, 33100 Udine, Italy
| | - Biao Tang
- Fields-CQAM Laboratory of Mathematics for Public Health (MfPH), York University, Toronto, Ontario Canada
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario Canada
| | - Nicola Luigi Bragazzi
- Fields-CQAM Laboratory of Mathematics for Public Health (MfPH), York University, Toronto, Ontario Canada
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario Canada
| | - Kyeongah Nah
- Fields-CQAM Laboratory of Mathematics for Public Health (MfPH), York University, Toronto, Ontario Canada
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario Canada
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, Ontario Canada
| | - Ali Asgary
- Disaster & Emergency Management, School of Administrative Studies & Advanced Disaster & Emergency Rapid-Response Simulation (ADERSIM), York University, Toronto, Ontario Canada
| | - V. Kumar Murty
- Department of Mathematics, University of Toronto, Toronto, Ontario Canada
- The Fields Institute for Research in Mathematical Sciences, Toronto, Ontario Canada
| | - Nicholas H. Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, St-Hyacinthe, Quebec Canada
| | - Jianhong Wu
- Fields-CQAM Laboratory of Mathematics for Public Health (MfPH), York University, Toronto, Ontario Canada
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, Ontario Canada
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22
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Ramsay LC, Crowcroft NS, Thomas S, Aruffo E, Teslya A, Heffernan JM, Gournis E, Hiebert J, Jaeger V, Jiaravuthisan M, Sharron J, Severini A, Deeks SL, Gubbay J, Mazzulli T, Sander B. Cost-effectiveness of measles control during elimination in Ontario, Canada, 2015. ACTA ACUST UNITED AC 2020; 24. [PMID: 30892178 PMCID: PMC6425553 DOI: 10.2807/1560-7917.es.2019.24.11.1800370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BackgroundGiven that measles is eliminated in Canada and measles immunisation coverage in Ontario is high, it has been questioned whether Ontario's measles outbreak response is worthwhile.AimOur objective was to determine cost-effectiveness of measles containment protocols in Ontario from the healthcare payer perspective.MethodsWe developed a decision-analysis model comparing Ontario's measles containment strategy (based on actual 2015 outbreak data) with a hypothetical 'modified response'. The modified scenario assumed 10% response costs with reduced case and contact tracing and no outbreak-associated vaccinations; it was based on local and provincial administrative and laboratory data and parameters from peer-reviewed literature. Short- and long-term health outcomes, quality-adjusted life years (QALYs) and costs discounted at 1.5%, were estimated. We conducted one- and two-way sensitivity analyses.ResultsThe 2015 outbreak in Ontario comprised 16 measles cases and an estimated 3,369 contacts. Predictive modelling suggested that the outbreak response prevented 16 outbreak-associated cases at a cost of CAD 1,213,491 (EUR 861,579). The incremental cost-effectiveness ratio was CAD 739,063 (EUR 524,735) per QALY gained for the outbreak response vs modified response. To meet the commonly accepted cost-effectiveness threshold of CAD 50,000 (EUR 35,500) per QALY gained, the outbreak response would have to prevent 94 measles cases. In sensitivity analyses, the findings were robust.ConclusionsOntario's measles outbreak response exceeds generally accepted cost-effectiveness thresholds and may not be the most efficient use of public health resources from a healthcare payer perspective. These findings should be balanced against benefits of increased vaccine coverage and maintaining elimination status.
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Affiliation(s)
- Lauren C Ramsay
- University Health Network, Eaton Building, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada.,Public Health Ontario, Toronto, Ontario, Canada
| | - Natasha S Crowcroft
- University of Toronto, Toronto, Ontario, Canada.,Public Health Ontario, Toronto, Ontario, Canada
| | | | | | | | | | - Effie Gournis
- Toronto Public Health, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Joanne Hiebert
- Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | | | | | | | - Alberto Severini
- University of Manitoba, Winnipeg, Manitoba, Canada.,Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Shelley L Deeks
- University of Toronto, Toronto, Ontario, Canada.,Public Health Ontario, Toronto, Ontario, Canada
| | | | - Tony Mazzulli
- University Health Network, Eaton Building, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada.,Public Health Ontario, Toronto, Ontario, Canada
| | - Beate Sander
- Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.,University Health Network, Eaton Building, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada.,Public Health Ontario, Toronto, Ontario, Canada
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23
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Tang B, Scarabel F, Bragazzi NL, McCarthy Z, Glazer M, Xiao Y, Heffernan JM, Asgary A, Ogden NH, Wu J. De-Escalation by Reversing the Escalation with a Stronger Synergistic Package of Contact Tracing, Quarantine, Isolation and Personal Protection: Feasibility of Preventing a COVID-19 Rebound in Ontario, Canada, as a Case Study. Biology (Basel) 2020; 9:E100. [PMID: 32429450 PMCID: PMC7284446 DOI: 10.3390/biology9050100] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 11/21/2022]
Abstract
Since the beginning of the COVID-19 pandemic, most Canadian provinces have gone through four distinct phases of social distancing and enhanced testing. A transmission dynamics model fitted to the cumulative case time series data permits us to estimate the effectiveness of interventions implemented in terms of the contact rate, probability of transmission per contact, proportion of isolated contacts, and detection rate. This allows us to calculate the control reproduction number during different phases (which gradually decreased to less than one). From this, we derive the necessary conditions in terms of enhanced social distancing, personal protection, contact tracing, quarantine/isolation strength at each escalation phase for the disease control to avoid a rebound. From this, we quantify the conditions needed to prevent epidemic rebound during de-escalation by simply reversing the escalation process.
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Affiliation(s)
- Biao Tang
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
- The Interdisciplinary Research Center for Mathematics and Life Sciences, Xi’an Jiaotong University, Xi’an 710049, China
| | - Francesca Scarabel
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
- CDLab—Computational Dynamics Laboratory, Department of Mathematics, Computer Science and Physics, University of Udine, 33100 Udine, Italy
| | - Nicola Luigi Bragazzi
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
| | - Zachary McCarthy
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
| | - Michael Glazer
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
| | - Yanyu Xiao
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, OH 45221-0025, USA;
| | - Jane M. Heffernan
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, Department of Mathematics & Statistics, York University, Toronto, ON M3J 1P3, Canada
| | - Ali Asgary
- Disaster & Emergency Management, School of Administrative Studies & Advanced Disaster & Emergency Rapid-response Simulation (ADERSIM), York University, Toronto, ON M3J 1P3, Canada;
| | - Nicholas Hume Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, St. Hyacinthe, QC J2S 2M2, Canada;
| | - Jianhong Wu
- Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; (B.T.); (F.S.); (N.L.B.); (Z.M.); (M.G.); (J.M.H.)
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24
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Nah K, Alavinejad M, Rahman A, Heffernan JM, Wu J. Impact of influenza vaccine-modified infectivity on attack rate, case fatality ratio and mortality. J Theor Biol 2020; 492:110190. [PMID: 32035827 DOI: 10.1016/j.jtbi.2020.110190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/03/2019] [Accepted: 02/02/2020] [Indexed: 10/25/2022]
Abstract
Generally, vaccines are designed to provide protection against infection (susceptibility), disease (symptoms and transmissibility), and/or complications. In a recent study of influenza vaccination, it was observed that vaccinated yet infected individuals experienced increased transmission levels. In this paper, using a mathematical model of infection and transmission, we study the impact of vaccine-modified effects, including susceptibility and infectivity, on important epidemiological outcomes of an immunization program. The balance between vaccine-modified susceptibility, infectivity and recovery needed in preventing an influenza outbreak, or in mitigating the health outcomes of the outbreak is studied using the SIRV-type of disease transmission model. We also investigate the impact of influenza vaccination program on the infection risk of vaccinated and non-vaccinated individuals.
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Affiliation(s)
- Kyeongah Nah
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, ON M3J 1P3, Canada; Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada
| | - Mahnaz Alavinejad
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, ON M3J 1P3, Canada; Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada
| | - Ashrafur Rahman
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, ON M3J 1P3, Canada; Department of Mathematics and Statistics, Oakland University, Rochester, MI 48309, USA
| | - Jane M Heffernan
- Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; Centre for Disease Modelling (CDM), York University, Toronto, ON M3J 1P3, Canada
| | - Jianhong Wu
- Laboratory for Industrial and Applied Mathematics, York University, Toronto, ON M3J 1P3, Canada; Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3, Canada; Centre for Disease Modelling (CDM), York University, Toronto, ON M3J 1P3, Canada; Fields-CQAM Laboratory of Mathematics for Public Health, York University, Toronto, ON M3J 1P3, Canada.
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25
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Hughes SL, Bolotin S, Khan S, Li Y, Johnson C, Friedman L, Tricco AC, Hahné SJM, Heffernan JM, Dabbagh A, Durrheim DN, Orenstein WA, Moss WJ, Jit M, Crowcroft NS. The effect of time since measles vaccination and age at first dose on measles vaccine effectiveness - A systematic review. Vaccine 2020; 38:460-469. [PMID: 31732326 PMCID: PMC6970218 DOI: 10.1016/j.vaccine.2019.10.090] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/16/2019] [Accepted: 10/27/2019] [Indexed: 12/04/2022]
Abstract
BACKGROUND In settings where measles has been eliminated, vaccine-derived immunity may in theory wane more rapidly due to a lack of immune boosting by circulating measles virus. We aimed to assess whether measles vaccine effectiveness (VE) waned over time, and if so, whether differentially in measles-eliminated and measles-endemic settings. METHODS We performed a systematic literature review of studies that reported VE and time since vaccination with measles-containing vaccine (MCV). We extracted information on case definition (clinical symptoms and/or laboratory diagnosis), method of vaccination status ascertainment (medical record or vaccine registry), as well as any biases which may have arisen from cold chain issues and a lack of an age at first dose of MCV. We then used linear regression to evaluate VE as a function of age at first dose of MCV and time since MCV. RESULTS After screening 14,782 citations, we identified three full-text articles from measles-eliminated settings and 33 articles from measles-endemic settings. In elimination settings, two-dose VE estimates increased as age at first dose of MCV increased and decreased as time since MCV increased; however, the small number of studies available limited interpretation. In measles-endemic settings, one-dose VE increased by 1.5% (95% CI 0.5, 2.5) for every month increase in age at first dose of MCV. We found no evidence of waning VE in endemic settings. CONCLUSIONS The paucity of data from measles-eliminated settings indicates that additional studies and approaches (such as studies using proxies including laboratory correlates of protection) are needed to answer the question of whether VE in measles-eliminated settings wanes. Age at first dose of MCV was the most important factor in determining VE. More VE studies need to be conducted in elimination settings, and standards should be developed for information collected and reported in such studies.
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Affiliation(s)
| | - Shelly Bolotin
- Public Health Ontario, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Ye Li
- Public Health Ontario, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Andrea C Tricco
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Susan J M Hahné
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Jane M Heffernan
- Centre for Disease Modelling, Department of Mathematics & Statistics, York University, Toronto, Ontario, Canada
| | - Alya Dabbagh
- Department of Immunisation, Vaccines, and Biologicals, World Health Organization, Geneva, Switzerland
| | - David N Durrheim
- Hunter New England Health, New Lambton Heights, New South Wales, Australia; School of Medicine and Public Health, University of Newcastle, New South Wales, Australia; Public Health and Tropical Medicine, James Cook University, Queensland, Australia
| | - Walter A Orenstein
- Emory University School of Medicine, Emory University, Atlanta, GA, United States; Emory Vaccine Center, Emory University, Atlanta, GA, United States
| | - William J Moss
- International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Mark Jit
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom; Modelling and Economics Unit, Public Health England, London, United Kingdom
| | - Natasha S Crowcroft
- Public Health Ontario, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; ICES, Toronto, Ontario, Canada.
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26
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Teslya A, Qesmi R, Wu J, Heffernan JM. A threshold delay model of HIV infection of newborn infants through breastfeeding. Infect Dis Model 2019; 4:188-214. [PMID: 31194190 PMCID: PMC6554533 DOI: 10.1016/j.idm.2019.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/17/2018] [Accepted: 05/04/2019] [Indexed: 11/13/2022] Open
Abstract
The breast milk of HIV infected women contains HIV virus particles, therefore children can become infected through breastfeeding. We develop a mathematical epidemiological model of HIV infection in infants, infected children and infected women that represents infection of an infant/child as a series of exposures, by incorporating within-host virus dynamics in the individuals exposed to the virus through breastfeeding. We show that repeated exposures of the infant/child via breastfeeding can cause bi-stability dynamics and, subsequently, infection persistence even when the epidemiological basic reproduction number R0 is less than unity. This feature of the model, due to a backward bifurcation, gives new insight into the control mechanisms of HIV disease through breastfeeding.
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Affiliation(s)
- Alexandra Teslya
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, Mathematics & Statistics, York University, M3J 1P3, Toronto, Canada
| | - Redouane Qesmi
- Superior School of Technology, Sidi Mohamed Ben Abdellah University, Fez 30000, Morocco
| | - Jianhong Wu
- Laboratory for Industrial and Applied Mathematics (LIAM), Centre for Disease Modelling (CDM), Advanced Disaster, Emergency and Rapid Simulation (ADERSIM), Faculty of Science, York University, Toronto, M3J 1P3, Canada
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, Mathematics & Statistics, York University, M3J 1P3, Toronto, Canada
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Zhou W, Xiao Y, Heffernan JM. A two-thresholds policy to interrupt transmission of West Nile Virus to birds. J Theor Biol 2018; 463:22-46. [PMID: 30550862 DOI: 10.1016/j.jtbi.2018.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/05/2018] [Accepted: 12/11/2018] [Indexed: 11/15/2022]
Abstract
This paper proposes a model of West Nile Virus (WNV) including threshold control policies concerning the culling of mosquitoes and birds under different conditions. Two thresholds are introduced to estimate whether and which control strategy should be implemented. For each mosquito threshold level [Formula: see text] the dynamical behaviour of the proposed non-smooth system is investigated as the bird threshold level [Formula: see text] varies, focusing on the existence of sliding domains, the existence of pseudo-equilibria, real or virtual of the endemic equilibria, global stability of these steady states, and the most interesting case of the occurrence of a novel globally asymptotically stable pseudo-attractor. The model solutions ultimately converge to a real equilibrium or a pseudo-equilibrium (if it exists), or a pseudo-attractor if no equilibrium is real and no pseudo-equilibrium exists. Here within, we show that the free system has a single stable endemic equilibrium under biologically reasonable assumptions, and show that when the control system has: (1) a bird-culling threshold that is above the bird equilibrium, culling has no advantage; (2) a bird-culling threshold that is below the bird equilibrium, but a mosquito-culling threshold that lies above the mosquito equilibrium, the infected bird population can be reduced but the infected mosquito population will remain the same; (3) a bird-culling threshold and a mosquito-culling threshold that both lie below their respective equilibrium values of the free system, then both the infected bird and mosquito populations can be reduced to lower levels. The results suggest that preset levels of the number of infected birds and infected mosquitoes can be maintained simultaneously when threshold values are chosen properly, which provides a possible control strategy when an emergent infectious disease cannot be eradicated immediately.
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Affiliation(s)
- Weike Zhou
- Department of Applied Mathematics, School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an, 710049, PR China.
| | - Yanni Xiao
- Department of Applied Mathematics, School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an, 710049, PR China.
| | - Jane M Heffernan
- Department of Mathematics & Statistics, York University, Toronto, ON, M3J 1P3, Canada.
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Rahman QA, Janmohamed T, Pirbaglou M, Clarke H, Ritvo P, Heffernan JM, Katz J. Defining and Predicting Pain Volatility in Users of the Manage My Pain App: Analysis Using Data Mining and Machine Learning Methods. J Med Internet Res 2018; 20:e12001. [PMID: 30442636 PMCID: PMC6265601 DOI: 10.2196/12001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/04/2018] [Accepted: 10/22/2018] [Indexed: 12/31/2022] Open
Abstract
Background Measuring and predicting pain volatility (fluctuation or variability in pain scores over time) can help improve pain management. Perceptions of pain and its consequent disabling effects are often heightened under the conditions of greater uncertainty and unpredictability associated with pain volatility. Objective This study aimed to use data mining and machine learning methods to (1) define a new measure of pain volatility and (2) predict future pain volatility levels from users of the pain management app, Manage My Pain, based on demographic, clinical, and app use features. Methods Pain volatility was defined as the mean of absolute changes between 2 consecutive self-reported pain severity scores within the observation periods. The k-means clustering algorithm was applied to users’ pain volatility scores at the first and sixth month of app use to establish a threshold discriminating low from high volatility classes. Subsequently, we extracted 130 demographic, clinical, and app usage features from the first month of app use to predict these 2 volatility classes at the sixth month of app use. Prediction models were developed using 4 methods: (1) logistic regression with ridge estimators; (2) logistic regression with Least Absolute Shrinkage and Selection Operator; (3) Random Forests; and (4) Support Vector Machines. Overall prediction accuracy and accuracy for both classes were calculated to compare the performance of the prediction models. Training and testing were conducted using 5-fold cross validation. A class imbalance issue was addressed using a random subsampling of the training dataset. Users with at least five pain records in both the predictor and outcome periods (N=782 users) are included in the analysis. Results k-means clustering algorithm was applied to pain volatility scores to establish a threshold of 1.6 to differentiate between low and high volatility classes. After validating the threshold using random subsamples, 2 classes were created: low volatility (n=611) and high volatility (n=171). In this class-imbalanced dataset, all 4 prediction models achieved 78.1% (611/782) to 79.0% (618/782) in overall accuracy. However, all models have a prediction accuracy of less than 18.7% (32/171) for the high volatility class. After addressing the class imbalance issue using random subsampling, results improved across all models for the high volatility class to greater than 59.6% (102/171). The prediction model based on Random Forests performs the best as it consistently achieves approximately 70% accuracy for both classes across 3 random subsamples. Conclusions We propose a novel method for measuring pain volatility. Cluster analysis was applied to divide users into subsets of low and high volatility classes. These classes were then predicted at the sixth month of app use with an acceptable degree of accuracy using machine learning methods based on the features extracted from demographic, clinical, and app use information from the first month.
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Affiliation(s)
- Quazi Abidur Rahman
- Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | | | - Meysam Pirbaglou
- School of Kinesiology & Health Science, York University, Toronto, ON, Canada
| | - Hance Clarke
- Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, ON, Canada
| | - Paul Ritvo
- School of Kinesiology & Health Science, York University, Toronto, ON, Canada.,Department of Psychology, York University, Toronto, ON, Canada
| | - Jane M Heffernan
- Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Joel Katz
- School of Kinesiology & Health Science, York University, Toronto, ON, Canada.,Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, ON, Canada.,Department of Psychology, York University, Toronto, ON, Canada
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Milwid RM, Frascoli F, Steben M, Heffernan JM. HPV Screening and Vaccination Strategies in an Unscreened Population: A Mathematical Modeling Study. Bull Math Biol 2018; 81:4313-4342. [DOI: 10.1007/s11538-018-0425-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 03/28/2018] [Indexed: 11/28/2022]
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Rahman QA, Janmohamed T, Pirbaglou M, Ritvo P, Heffernan JM, Clarke H, Katz J. Patterns of User Engagement With the Mobile App, Manage My Pain: Results of a Data Mining Investigation. JMIR Mhealth Uhealth 2017; 5:e96. [PMID: 28701291 PMCID: PMC5529741 DOI: 10.2196/mhealth.7871] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 06/07/2017] [Accepted: 06/28/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Pain is one of the most prevalent health-related concerns and is among the top 3 most common reasons for seeking medical help. Scientific publications of data collected from pain tracking and monitoring apps are important to help consumers and healthcare professionals select the right app for their use. OBJECTIVE The main objectives of this paper were to (1) discover user engagement patterns of the pain management app, Manage My Pain, using data mining methods; and (2) identify the association between several attributes characterizing individual users and their levels of engagement. METHODS User engagement was defined by 2 key features of the app: longevity (number of days between the first and last pain record) and number of records. Users were divided into 5 user engagement clusters employing the k-means clustering algorithm. Each cluster was characterized by 6 attributes: gender, age, number of pain conditions, number of medications, pain severity, and opioid use. Z tests and chi-square tests were used for analyzing categorical attributes. Effects of gender and cluster on numerical attributes were analyzed using 2-way analysis of variances (ANOVAs) followed up by pairwise comparisons using Tukey honest significant difference (HSD). RESULTS The clustering process produced 5 clusters representing different levels of user engagement. The proportion of males and females was significantly different in 4 of the 5 clusters (all P ≤.03). The proportion of males was higher than females in users with relatively high longevity. Mean ages of users in 2 clusters with high longevity were higher than users from other 3 clusters (all P <.001). Overall, males were significantly older than females (P <.001). Across clusters, females reported more pain conditions than males (all P <.001). Users from highly engaged clusters reported taking more medication than less engaged users (all P <.001). Females reported taking a greater number of medications than males (P =.04). In 4 of 5 clusters, the percentage of males taking an opioid was significantly greater (all P ≤.05) than that of females. The proportion of males with mild pain was significantly higher than that of females in 3 clusters (all P ≤.008). CONCLUSIONS Although most users of the app reported being female, male users were more likely to be highly engaged in the app. Users in the most engaged clusters self-reported a higher number of pain conditions, a higher number of current medications, and a higher incidence of opioid usage. The high engagement by males in these clusters does not appear to be driven by pain severity which may, in part, be the case for females. Use of a mobile pain app may be relatively more attractive to highly-engaged males than highly-engaged females, and to those with relatively more complex chronic pain problems.
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Affiliation(s)
- Quazi Abidur Rahman
- Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | | | - Meysam Pirbaglou
- School of Kinesiology & Health Science, York University, Toronto, ON, Canada
| | - Paul Ritvo
- School of Kinesiology & Health Science, York University, Toronto, ON, Canada
- Department of Psychology, York University, Toronto, ON, Canada
| | - Jane M Heffernan
- Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Hance Clarke
- Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, ON, Canada
| | - Joel Katz
- School of Kinesiology & Health Science, York University, Toronto, ON, Canada
- Department of Psychology, York University, Toronto, ON, Canada
- Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, ON, Canada
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Espindola AL, Varughese M, Laskowski M, Shoukat A, Heffernan JM, Moghadas SM. Strategies for halting the rise of multidrug resistant TB epidemics: assessing the effect of early case detection and isolation. Int Health 2017; 9:80-90. [PMID: 28338827 DOI: 10.1093/inthealth/ihw059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 12/21/2016] [Indexed: 11/14/2022] Open
Abstract
Background The increasing rates of multidrug resistant TB (MDR-TB) have posed the question of whether control programs under enhanced directly observed treatment, short-course (DOTS-Plus) are sufficient or implemented optimally. Despite enhanced efforts on early case detection and improved treatment regimens, direct transmission of MDR-TB remains a major hurdle for global TB control. Methods We developed an agent-based simulation model of TB dynamics to evaluate the effect of transmission reduction measures on the incidence of MDR-TB. We implemented a 15-day isolation period following the start of treatment in active TB cases. The model was parameterized with the latest estimates derived from the published literature. Results We found that if high rates (over 90%) of TB case identification are achieved within 4 weeks of developing active TB, then a 15-day patient isolation strategy with 50% effectiveness in interrupting disease transmission leads to 10% reduction in the incidence of MDR-TB over 10 years. If transmission is fully prevented, the rise of MDR-TB can be halted within 10 years, but the temporal reduction of MDR-TB incidence remains below 20% in this period. Conclusions The impact of transmission reduction measures on the TB incidence depends critically on the rates and timelines of case identification. The high costs and adverse effects associated with MDR-TB treatment warrant increased efforts and investments on measures that can interrupt direct transmission through early case detection.
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Affiliation(s)
- Aquino L Espindola
- Departamento de Física, Instituto de Ciéncias Exatas-ICEx, Universidade Federal Fluminense, Volta Redonda, RJ, 27.213-145Brazil
| | - Marie Varughese
- Department of Mathematical and Statistical Sciences and Department of Public Health Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Marek Laskowski
- Agent-Based Modelling Laboratory, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada
| | - Affan Shoukat
- Agent-Based Modelling Laboratory, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada
| | - Jane M Heffernan
- Centre for Disease Modelling, Department of Mathematics and Statistics, York University, Toronto, ON, M3J 1P3, Canada
| | - Seyed M Moghadas
- Agent-Based Modelling Laboratory, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada
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Abstract
Understanding the mechanisms governing host-pathogen kinetics is important and can guide human interventions. In-host mathematical models, together with biological data, have been used in this endeavor. In this review, we present basic models used to describe acute and chronic pathogenic infections. We highlight the power of model predictions, the role of drug therapy, and advantage of considering the dynamics of immune responses. We also present the limitations of these models due in part to the trade-off between the complexity of the model and their predictive power, and the challenges a modeler faces in determining the appropriate formulation for a given problem.
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Affiliation(s)
- Stanca M. Ciupe
- Department of Mathematics, Virginia Tech, Blacksburg, VA, USA
| | - Jane M. Heffernan
- Centre for Disease Modelling, Department of Mathematics & Statistics, York University, Toronto, ON, Canada
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Yan AWC, Cao P, Heffernan JM, McVernon J, Quinn KM, La Gruta NL, Laurie KL, McCaw JM. Corrigendum to ''Modelling cross-reactivity and memory in the cellular adaptive immune response to influenza infection in the host'' [J.Theor. Biol. 413 (2017) 34-49]. J Theor Biol 2017; 419:394. [PMID: 28363398 DOI: 10.1016/j.jtbi.2017.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ada W C Yan
- School of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australia
| | - Pengxing Cao
- School of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jane M Heffernan
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada M3J 1P3; Modelling Infection and Immunity Lab, Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, Ontario, Canada M3J1P3
| | - Jodie McVernon
- Doherty Epidemiology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, VIC 3010, Australia; Modelling and Simulation, Infection and Immunity Theme, Murdoch Children's Research Institute, Parkville, VIC 3052, Australia
| | - Kylie M Quinn
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia; Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Nicole L La Gruta
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia; Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Karen L Laurie
- WHO Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia; School of Applied and Biomedical Sciences, Federation University, Churchill, VIC 3842, Australia; Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia
| | - James M McCaw
- School of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, VIC 3010, Australia; Modelling and Simulation, Infection and Immunity Theme, Murdoch Children's Research Institute, Parkville, VIC 3052, Australia.
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Cao P, Wang Z, Yan AWC, McVernon J, Xu J, Heffernan JM, Kedzierska K, McCaw JM. On the Role of CD8 + T Cells in Determining Recovery Time from Influenza Virus Infection. Front Immunol 2016; 7:611. [PMID: 28066421 PMCID: PMC5167728 DOI: 10.3389/fimmu.2016.00611] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/02/2016] [Indexed: 01/02/2023] Open
Abstract
Myriad experiments have identified an important role for CD8+ T cell response mechanisms in determining recovery from influenza A virus infection. Animal models of influenza infection further implicate multiple elements of the immune response in defining the dynamical characteristics of viral infection. To date, influenza virus models, while capturing particular aspects of the natural infection history, have been unable to reproduce the full gamut of observed viral kinetic behavior in a single coherent framework. Here, we introduce a mathematical model of influenza viral dynamics incorporating innate, humoral, and cellular immune components and explore its properties with a particular emphasis on the role of cellular immunity. Calibrated against a range of murine data, our model is capable of recapitulating observed viral kinetics from a multitude of experiments. Importantly, the model predicts a robust exponential relationship between the level of effector CD8+ T cells and recovery time, whereby recovery time rapidly decreases to a fixed minimum recovery time with an increasing level of effector CD8+ T cells. We find support for this relationship in recent clinical data from influenza A (H7N9) hospitalized patients. The exponential relationship implies that people with a lower level of naive CD8+ T cells may receive significantly more benefit from induction of additional effector CD8+ T cells arising from immunological memory, itself established through either previous viral infection or T cell-based vaccines.
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Affiliation(s)
- Pengxing Cao
- School of Mathematics and Statistics, The University of Melbourne , Melbourne, VIC , Australia
| | - Zhongfang Wang
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne and Royal Melbourne Hospital, Melbourne, VIC, Australia; Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Ada W C Yan
- School of Mathematics and Statistics, The University of Melbourne , Melbourne, VIC , Australia
| | - Jodie McVernon
- Doherty Epidemiology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne and Royal Melbourne Hospital, Melbourne, VIC, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia; Modelling and Simulation, Infection and Immunity Theme, Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Jianqing Xu
- Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Institutes of Biomedical Sciences, Fudan University , Shanghai , China
| | - Jane M Heffernan
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, York Institute for Health Research, Mathematics and Statistics, York University , Toronto, ON , Canada
| | - Katherine Kedzierska
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne and Royal Melbourne Hospital , Melbourne, VIC , Australia
| | - James M McCaw
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia; Modelling and Simulation, Infection and Immunity Theme, Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
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Yan AWC, Cao P, Heffernan JM, McVernon J, Quinn KM, La Gruta NL, Laurie KL, McCaw JM. Modelling cross-reactivity and memory in the cellular adaptive immune response to influenza infection in the host. J Theor Biol 2016; 413:34-49. [PMID: 27856216 DOI: 10.1016/j.jtbi.2016.11.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 11/02/2016] [Accepted: 11/05/2016] [Indexed: 01/05/2023]
Abstract
The cellular adaptive immune response plays a key role in resolving influenza infection. Experiments where individuals are successively infected with different strains within a short timeframe provide insight into the underlying viral dynamics and the role of a cross-reactive immune response in resolving an acute infection. We construct a mathematical model of within-host influenza viral dynamics including three possible factors which determine the strength of the cross-reactive cellular adaptive immune response: the initial naive T cell number, the avidity of the interaction between T cells and the epitopes presented by infected cells, and the epitope abundance per infected cell. Our model explains the experimentally observed shortening of a second infection when cross-reactivity is present, and shows that memory in the cellular adaptive immune response is necessary to protect against a second infection.
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Affiliation(s)
- Ada W C Yan
- School of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australia
| | - Pengxing Cao
- School of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jane M Heffernan
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada M3J 1P3; Modelling Infection and Immunity Lab, Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, Ontario, Canada M3J 1P3
| | - Jodie McVernon
- Doherty Epidemiology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, VIC 3010, Australia; Modelling and Simulation, Infection and Immunity Theme, Murdoch Children's Research Institute, Parkville, VIC 3052, Australia
| | - Kylie M Quinn
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia; Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Nicole L La Gruta
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia; Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Karen L Laurie
- WHO Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia; School of Applied and Biomedical Sciences, Federation University, Churchill, VIC 3842, Australia; Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia
| | - James M McCaw
- School of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, VIC 3010, Australia; Modelling and Simulation, Infection and Immunity Theme, Murdoch Children's Research Institute, Parkville, VIC 3052, Australia.
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Addington CP, Dharmawaj S, Heffernan JM, Sirianni RW, Stabenfeldt SE. Hyaluronic acid-laminin hydrogels increase neural stem cell transplant retention and migratory response to SDF-1α. Matrix Biol 2016; 60-61:206-216. [PMID: 27645115 DOI: 10.1016/j.matbio.2016.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/14/2016] [Accepted: 09/12/2016] [Indexed: 01/29/2023]
Abstract
The chemokine SDF-1α plays a critical role in mediating stem cell response to injury and disease and has specifically been shown to mobilize neural progenitor/stem cells (NPSCs) towards sites of neural injury. Current neural transplant paradigms within the brain suffer from low rates of retention and engraftment after injury. Therefore, increasing transplant sensitivity to injury-induced SDF-1α represents a method for increasing neural transplant efficacy. Previously, we have reported on a hyaluronic acid-laminin based hydrogel (HA-Lm gel) that increases NPSC expression of SDF-1α receptor, CXCR4, and subsequently, NPSC chemotactic migration towards a source of SDF-1α in vitro. The study presented here investigates the capacity of the HA-Lm gel to promote NPSC response to exogenous SDF-1α in vivo. We observed the HA-Lm gel to significantly increase NPSC transplant retention and migration in response to SDF-1α in a manner critically dependent on signaling via the SDF-1α-CXCR4 axis. This work lays the foundation for development of a more effective cell therapy for neural injury, but also has broader implications in the fields of tissue engineering and regenerative medicine given the essential roles of SDF-1α across injury and disease states.
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Affiliation(s)
- C P Addington
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States
| | - S Dharmawaj
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, United States
| | - J M Heffernan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States; Barrow Brain Tumor Research Center, Barrow Neurological Institute, Phoenix, AZ, United States
| | - R W Sirianni
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States; Barrow Brain Tumor Research Center, Barrow Neurological Institute, Phoenix, AZ, United States
| | - S E Stabenfeldt
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States.
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Dubé E, Gagnon D, Ouakki M, Bettinger JA, Guay M, Halperin S, Wilson K, Graham J, Witteman HO, MacDonald S, Fisher W, Monnais L, Tran D, Gagneur A, Guichon J, Saini V, Heffernan JM, Meyer S, Driedger SM, Greenberg J, MacDougall H. Understanding Vaccine Hesitancy in Canada: Results of a Consultation Study by the Canadian Immunization Research Network. PLoS One 2016; 11:e0156118. [PMID: 27257809 PMCID: PMC4892544 DOI: 10.1371/journal.pone.0156118] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/08/2016] [Indexed: 11/18/2022] Open
Abstract
"Vaccine hesitancy" is a concept now frequently used in vaccination discourse. The increased popularity of this concept in both academic and public health circles is challenging previously held perspectives that individual vaccination attitudes and behaviours are a simple dichotomy of accept or reject. A consultation study was designed to assess the opinions of experts and health professionals concerning the definition, scope, and causes of vaccine hesitancy in Canada. We sent online surveys to two panels (1- vaccination experts and 2- front-line vaccine providers). Two questionnaires were completed by each panel, with data from the first questionnaire informing the development of questions for the second. Our participants defined vaccine hesitancy as an attitude (doubts, concerns) as well as a behaviour (refusing some / many vaccines, delaying vaccination). Our findings also indicate that both vaccine experts and front-line vaccine providers have the perception that vaccine rates have been declining and consider vaccine hesitancy an important issue to address in Canada. Diffusion of negative information online and lack of knowledge about vaccines were identified as the key causes of vaccine hesitancy by the participants. A common understanding of vaccine hesitancy among researchers, public health experts, policymakers and health care providers will better guide interventions that can more effectively address vaccine hesitancy within Canada.
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Affiliation(s)
- Eve Dubé
- Département de médecine sociale et préventive, Université Laval, Québec, Québec, Canada
- Maladies infectieuses, Institut national de santé publique du Québec, Québec, Québec, Canada
- Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec–Université Laval, Québec, Québec, Canada
| | - Dominique Gagnon
- Maladies infectieuses, Institut national de santé publique du Québec, Québec, Québec, Canada
| | - Manale Ouakki
- Maladies infectieuses, Institut national de santé publique du Québec, Québec, Québec, Canada
| | - Julie A. Bettinger
- Vaccine Evaluation Center, BC Children’s Hospital, and University of British Columbia, Vancouver, British Columbia, Canada
| | - Maryse Guay
- Maladies infectieuses, Institut national de santé publique du Québec, Québec, Québec, Canada
- Département des sciences de la santé communautaire, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Scott Halperin
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kumanan Wilson
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Janice Graham
- Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Holly O. Witteman
- Département de médecine familiale et de médecine d’urgence, Université Laval, Québec, Québec, Canada
- Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec–Université Laval, Québec, Québec, Canada
| | - Shannon MacDonald
- Nursing Faculty, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - William Fisher
- Department of Psychology, University of Western Ontario, London, Ontario, Canada
| | - Laurence Monnais
- Département d'Histoire, Université de Montréal, Montréal, Québec, Canada
| | - Dat Tran
- Division of Infectious Diseases, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Arnaud Gagneur
- Département de pédiatrie, Service de néonatologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Juliet Guichon
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Vineet Saini
- Department of Production Animal Health, University of Calgary, Calgary, Alberta, Canada
- Alberta Health Services, Calgary, Alberta, Canada
| | - Jane M. Heffernan
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada
| | - Samantha Meyer
- School of Public Health and Health Systems, University of Waterloo, Waterloo, Ontario, Canada
| | - S. Michelle Driedger
- Department of Community Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Joshua Greenberg
- School of Journalism and Communication, Carleton University, Ottawa, Ontario, Canada
| | - Heather MacDougall
- Department of History, University of Waterloo, Waterloo, Ontario, Canada
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Collinson S, Khan K, Heffernan JM. The Effects of Media Reports on Disease Spread and Important Public Health Measurements. PLoS One 2015; 10:e0141423. [PMID: 26528909 PMCID: PMC4631512 DOI: 10.1371/journal.pone.0141423] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/08/2015] [Indexed: 11/19/2022] Open
Abstract
Controlling the spread of influenza to reduce the effects of infection on a population is an important mandate of public health. Mass media reports on an epidemic or pandemic can provide important information to the public, and in turn, can induce positive healthy behaviour practices (i.e., handwashing, social distancing) in the individuals, that will reduce the probability of contracting the disease. Mass media fatigue, however, can dampen these effects. Mathematical models can be used to study the effects of mass media reports on epidemic/pandemic outcomes. In this study we employ a stochastic agent based model to provide a quantification of mass media reports on the variability in important public health measurements. We also include mass media report data compiled by the Global Public Health Intelligence Network, to study the effects of mass media reports in the 2009 H1N1 pandemic. We find that the report rate and the rate at which individuals relax their healthy behaviours (media fatigue) greatly affect the variability in important public health measurements. When the mass media reporting data is included in the model, two peaks of infection result.
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Affiliation(s)
- Shannon Collinson
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, York University, Toronto, Canada
- Mathematics & Statistics, York University, Toronto, Canada
| | - Kamran Khan
- Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Canada
- Department of Medicine, Division of Infectious Diseases, University of Toronto, Toronto, Canada
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, York University, Toronto, Canada
- Mathematics & Statistics, York University, Toronto, Canada
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Addington CP, Heffernan JM, Millar-Haskell CS, Tucker EW, Sirianni RW, Stabenfeldt SE. Enhancing neural stem cell response to SDF-1α gradients through hyaluronic acid-laminin hydrogels. Biomaterials 2015; 72:11-9. [PMID: 26340314 DOI: 10.1016/j.biomaterials.2015.08.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 08/18/2015] [Indexed: 12/19/2022]
Abstract
Traumatic brain injury (TBI) initiates an expansive biochemical insult that is largely responsible for the long-term dysfunction associated with TBI; however, current clinical treatments fall short of addressing these underlying sequelae. Pre-clinical investigations have used stem cell transplantation with moderate success, but are plagued by staggeringly low survival and engraftment rates (2-4%). As such, providing cell transplants with the means to better dynamically respond to injury-related signals within the transplant microenvironment may afford improved transplantation survival and engraftment rates. The chemokine stromal cell-derived factor-1α (SDF-1α) is a potent chemotactic signal that is readily present after TBI. In this study, we sought to develop a transplantation vehicle to ultimately enhance the responsiveness of neural transplants to injury-induced SDF-1α. Specifically, we hypothesize that a hyaluronic acid (HA) and laminin (Lm) hydrogel would promote 1. upregulated expression of the SDF-1α receptor CXCR4 in neural progenitor/stem cells (NPSCs) and 2. enhanced NPSC migration in response to SDF-1α gradients. We demonstrated successful development of a HA-Lm hydrogel and utilized standard protein and cellular assays to probe NPSC CXCR4 expression and NPSC chemotactic migration. The findings demonstrated that NPSCs significantly increased CXCR4 expression after 48 h of culture on the HA-Lm gel in a manner critically dependent on both HA and laminin. Moreover, the HA-Lm hydrogel significantly increased NPSC chemotactic migration in response to SDF-1α at 48 h, an effect that was critically dependent on HA, laminin and the SDF-1α gradient. Therefore, this hydrogel serves to 1. prime NPSCs for the injury microenvironment and 2. provide the appropriate infrastructure to support migration into the surrounding tissue, equipping cells with the tools to more effectively respond to the injury microenvironment.
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Affiliation(s)
- C P Addington
- School of Biological and Health Systems Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA
| | - J M Heffernan
- School of Biological and Health Systems Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA; Barrow Brain Tumor Research Center, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ 85013, USA
| | - C S Millar-Haskell
- School of Biological and Health Systems Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA
| | - E W Tucker
- School of Biological and Health Systems Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA
| | - R W Sirianni
- School of Biological and Health Systems Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA; Barrow Brain Tumor Research Center, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ 85013, USA
| | - S E Stabenfeldt
- School of Biological and Health Systems Engineering, Arizona State University, P.O. Box 879709, Tempe, AZ 85287-9709, USA.
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Laurie KL, Guarnaccia TA, Carolan LA, Yan AWC, Aban M, Petrie S, Cao P, Heffernan JM, McVernon J, Mosse J, Kelso A, McCaw JM, Barr IG. Interval Between Infections and Viral Hierarchy Are Determinants of Viral Interference Following Influenza Virus Infection in a Ferret Model. J Infect Dis 2015; 212:1701-10. [PMID: 25943206 PMCID: PMC4633756 DOI: 10.1093/infdis/jiv260] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/23/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Epidemiological studies suggest that, following infection with influenza virus, there is a short period during which a host experiences a lower susceptibility to infection with other influenza viruses. This viral interference appears to be independent of any antigenic similarities between the viruses. We used the ferret model of human influenza to systematically investigate viral interference. METHODS Ferrets were first infected then challenged 1-14 days later with pairs of influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B viruses circulating in 2009 and 2010. RESULTS Viral interference was observed when the interval between initiation of primary infection and subsequent challenge was <1 week. This effect was virus specific and occurred between antigenically related and unrelated viruses. Coinfections occurred when 1 or 3 days separated infections. Ongoing shedding from the primary virus infection was associated with viral interference after the secondary challenge. CONCLUSIONS The interval between infections and the sequential combination of viruses were important determinants of viral interference. The influenza viruses in this study appear to have an ordered hierarchy according to their ability to block or delay infection, which may contribute to the dominance of different viruses often seen in an influenza season.
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Affiliation(s)
- Karen L Laurie
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity School of Applied and Biomedical Sciences, Federation University, Churchill, Australia
| | - Teagan A Guarnaccia
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity School of Applied and Biomedical Sciences, Federation University, Churchill, Australia
| | - Louise A Carolan
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity
| | - Ada W C Yan
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne
| | - Malet Aban
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity
| | - Stephen Petrie
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne
| | - Pengxing Cao
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne
| | - Jane M Heffernan
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne Modelling Infection and Immunity Laboratory, Centre for Disease Modelling, York Institute for Health Research Program in Mathematics and Statistics, York University, Toronto, Canada
| | - Jodie McVernon
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne Modelling and Simulation Research Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne
| | - Jennifer Mosse
- School of Applied and Biomedical Sciences, Federation University, Churchill, Australia
| | - Anne Kelso
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity
| | - James M McCaw
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne Modelling and Simulation Research Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne
| | - Ian G Barr
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at the Peter Doherty Institute for Infection and Immunity School of Applied and Biomedical Sciences, Federation University, Churchill, Australia
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Recoskie J, Heffernan JM, Jankowski HK. A note on statistical and biological communication: a case study of the 2009 H1N1 pandemic. BMC Res Notes 2014; 7:939. [PMID: 25526663 PMCID: PMC4326473 DOI: 10.1186/1756-0500-7-939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 11/06/2014] [Indexed: 11/23/2022] Open
Abstract
Background Many academic fields contribute to medical and health research. As a result, due to the various backgrounds of these disciplines, inference and interpretation of study findings can be misconstrued. Results In a recent survey of the 2009 H1N1 literature we found many instances where semantic and statistical misinterpretation or miscommunication could potentially arise. We provide examples where miscommunication or misinterpretation of study results can mislead the interdisciplinary reader. We also provide some additional background on statistical methodology and theory for the interested reader. Discussion This work presented some examples where statistical misinterpretation or miscommunication could arise in the H1N1 literature. However, similar challenges are encountered in other subjects and disciplines. To reduce the probability of this occurring it is necessary that (1) readers consider papers with a critical eye and approach citations with caution; (2) authors take more care to present study methods with more clarity. Reproducibility of the study results would greatly aid readers in their ability to understand and interpret the given findings.
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Affiliation(s)
| | - Jane M Heffernan
- Department of Mathematics and Statistics, York University, Toronto, ON, Canada.
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Dafilis MP, Frascoli F, McVernon J, Heffernan JM, McCaw JM. Dynamical crises, multistability and the influence of the duration of immunity in a seasonally-forced model of disease transmission. Theor Biol Med Model 2014; 11:43. [PMID: 25280872 PMCID: PMC4200138 DOI: 10.1186/1742-4682-11-43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/20/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Highly successful strategies to make populations more resilient to infectious diseases, such as childhood vaccinations programs, may nonetheless lead to unpredictable outcomes due to the interplay between seasonal variations in transmission and a population's immune status. METHODS Motivated by the study of diseases such as pertussis we introduce a seasonally-forced susceptible-infectious-recovered model of disease transmission with waning and boosting of immunity. We study the system's dynamical properties using a combination of numerical simulations and bifurcation techniques, paying particular attention to the properties of the initial condition space. RESULTS We find that highly unpredictable behaviour can be triggered by changes in biologically relevant model parameters such as the duration of immunity. In the particular system we analyse--used in the literature to study pertussis dynamics--we identify the presence of an initial-condition landscape containing three coexisting attractors. The system's response to interventions which perturb population immunity (e.g. vaccination "catch-up" campaigns) is therefore difficult to predict. CONCLUSION Given the increasing use of models to inform policy decisions regarding vaccine introduction and scheduling and infectious diseases intervention policy more generally, our findings highlight the importance of thoroughly investigating the dynamical properties of those models to identify key areas of uncertainty. Our findings suggest that the often stated tension between capturing biological complexity and utilising mathematically simple models is perhaps more nuanced than generally suggested. Simple dynamical models, particularly those which include forcing terms, can give rise to incredibly complex behaviour.
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Affiliation(s)
| | | | | | | | - James M McCaw
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne VIC, Australia.
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Dafilis MP, Frascoli F, McVernon J, Heffernan JM, McCaw JM. The dynamical consequences of seasonal forcing, immune boosting and demographic change in a model of disease transmission. J Theor Biol 2014; 361:124-32. [PMID: 25106793 DOI: 10.1016/j.jtbi.2014.07.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 11/28/2022]
Abstract
The impact of seasonal effects on the time course of an infectious disease can be dramatic. Seasonal fluctuations in the transmission rate for an infectious disease are known mathematically to induce cyclical behaviour and drive the onset of multistable and chaotic dynamics. These properties of forced dynamical systems have previously been used to explain observed changes in the period of outbreaks of infections such as measles, varicella (chickenpox), rubella and pertussis (whooping cough). Here, we examine in detail the dynamical properties of a seasonally forced extension of a model of infection previously used to study pertussis. The model is novel in that it includes a non-linear feedback term capturing the interaction between exposure and the duration of protection against re-infection. We show that the presence of limit cycles and multistability in the unforced system give rise to complex and intricate behaviour as seasonal forcing is introduced. Through a mixture of numerical simulation and bifurcation analysis, we identify and explain the origins of chaotic regions of parameter space. Furthermore, we identify regions where saddle node lines and period-doubling cascades of different orbital periods overlap, suggesting that the system is particularly sensitive to small perturbations in its parameters and prone to multistable behaviour. From a public health point of view - framed through the 'demographic transition' whereby a population׳s birth rate drops over time (and life-expectancy commensurately increases) - we argue that even weak levels of seasonal-forcing and immune boosting may contribute to the myriad of complex and unexpected epidemiological behaviours observed for diseases such as pertussis. Our approach helps to contextualise these epidemiological observations and provides guidance on how to consider the potential impact of vaccination programs.
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Affiliation(s)
- Mathew P Dafilis
- Melbourne School of Population and Global Health, The University of Melbourne, VIC, Australia; Murdoch Childrens Research Institute, VIC, Australia
| | - Federico Frascoli
- Department of Mathematics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, VIC, Australia
| | - Jodie McVernon
- Melbourne School of Population and Global Health, The University of Melbourne, VIC, Australia; Murdoch Childrens Research Institute, VIC, Australia
| | - Jane M Heffernan
- Melbourne School of Population and Global Health, The University of Melbourne, VIC, Australia; Modelling Infection and Immunity Lab, Centre for Disease Modelling, York Institute for Health Research, Canada; Mathematics and Statistics, York University, ON, Canada
| | - James M McCaw
- Melbourne School of Population and Global Health, The University of Melbourne, VIC, Australia; Murdoch Childrens Research Institute, VIC, Australia.
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Abstract
BACKGROUND Mass media is used to inform individuals regarding diseases within a population. The effects of mass media during disease outbreaks have been studied in the mathematical modelling literature, by including 'media functions' that affect transmission rates in mathematical epidemiological models. The choice of function to employ, however, varies, and thus, epidemic outcomes that are important to inform public health may be affected. METHODS We present a survey of the disease modelling literature with the effects of mass media. We present a comparison of the functions employed and compare epidemic results parameterized for an influenza outbreak. An agent-based Monte Carlo simulation is created to access variability around key epidemic measurements, and a sensitivity analysis is completed in order to gain insight into which model parameters have the largest influence on epidemic outcomes. RESULTS Epidemic outcome depends on the media function chosen. Parameters that most influence key epidemic outcomes are different for each media function. CONCLUSION Different functions used to represent the effects of media during an epidemic will affect the outcomes of a disease model, including the variability in key epidemic measurements. Thus, media functions may not best represent the effects of media during an epidemic. A new method for modelling the effects of media needs to be considered.
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Affiliation(s)
- Shannon Collinson
- Department of Mathematics & Statistics, York University, Toronto, Canada
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, Canada
| | - Jane M Heffernan
- Department of Mathematics & Statistics, York University, Toronto, Canada
- Modelling Infection and Immunity Lab, Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, Canada
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Abstract
Background Pre-existing cellular immunity has been recognized as one of the key factors in determining the outcome of influenza infection by reducing the likelihood of clinical disease and mitigates illness. Whether, and to what extent, the effect of this self-protective mechanism can be captured in the population dynamics of an influenza epidemic has not been addressed. Methods We applied previous findings regarding T-cell cross-reactivity between the 2009 pandemic H1N1 strain and seasonal H1N1 strains to investigate the possible changes in the magnitude and peak time of the epidemic. Continuous Monte-Carlo Markov Chain (MCMC) model was employed to simulate the role of pre-existing immunity on the dynamical behavior of epidemic peak. Results From the MCMC model simulations, we observed that, as the size of subpopulation with partially effective pre-existing immunity increases, the mean magnitude of the epidemic peak decreases, while the mean time to reach the peak increases. However, the corresponding ranges of these variations are relatively small. Conclusions Our study concludes that the effective role of pre-existing immunity in alleviating disease outcomes (e.g., hospitalization) of novel influenza virus remains largely undetectable in population dynamics of an epidemic. The model outcome suggests that rapid clinical investigations on T-cell assays remain crucial for determining the protection level conferred by pre-existing cellular responses in the face of an emerging influenza virus.
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Lou Y, Qesmi R, Wang Q, Steben M, Wu J, Heffernan JM. Epidemiological impact of a genital herpes type 2 vaccine for young females. PLoS One 2012; 7:e46027. [PMID: 23071536 PMCID: PMC3469571 DOI: 10.1371/journal.pone.0046027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 08/27/2012] [Indexed: 11/25/2022] Open
Abstract
Genital Herpes, which is caused by Herpes Simplex Virus-1 or -2 (HSV-1, -2, predominantly HSV-2) is a sexually transmitted infection (STI) that causes a chronic latent infection with outbreak episodes linked to transmission. Antiviral therapies are effective in reducing viral shedding during these episodes, but are ineffective as a whole since many outbreaks are asymptomatic or have mild symptoms. Thus, the development of a vaccine for genital herpes is needed to control this disease. The question of how to implement such a vaccine program is an important one, and may be similar to the vaccination program for Human Papilloma Virus (HPV) for young females. We have developed a mathematical model to describe the epidemiology of vaccination targeting young females against HSV-2. The model population is delineated with respect to age group, sexual activity and infection status including oral infection of HSV-1, which may affect vaccine efficacy. A threshold parameter R(C), which determines the level of vaccine uptake needed to eradicate HSV-2, is found. Computer simulation shows that an adolescent-only vaccination program may be effective in eliminating HSV-2 disease, however, the success of extinction greatly depends on the level of vaccine uptake, the vaccine efficacy, the age of sexual maturity and safe sex practices. However, the time course of eradication would take many years. We also investigate the prevalence of infection in the total population and in women between 16-30 years of age before and after vaccination has been introduced, and show that the adolescent-only vaccination program can be effective in reducing disease prevalence in these populations depending on the level of vaccine uptake and vaccine efficacy. This will also result in a decrease of maternal-fetal transmission of HSV-2 infection. Another important, if commonsense, conclusion is that vaccination of some females reduces infection in men, which then reduces infection in women.
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Affiliation(s)
- Yijun Lou
- Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Applied Mathematics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Redouane Qesmi
- Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Ecole Superieure de Technologie, Université Sidi Mohamed Ben Abdellah, Fès, Morocco
| | - Qian Wang
- Mathematics and Statistics, York University, Toronto, Ontario, Canada
| | - Marc Steben
- Institut National de Santé Publique du Québec, Montréal, Québec, Canada
| | - Jianhong Wu
- Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, Ontario, Canada
| | - Jane M. Heffernan
- Mathematics and Statistics, York University, Toronto, Ontario, Canada
- Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, Ontario, Canada
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Wang Y, Zhou Y, Brauer F, Heffernan JM. Viral dynamics model with CTL immune response incorporating antiretroviral therapy. J Math Biol 2012; 67:901-34. [DOI: 10.1007/s00285-012-0580-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 06/28/2012] [Indexed: 01/01/2023]
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Duvvuri VRSK, Moghadas SM, Guo H, Duvvuri B, Heffernan JM, Fisman DN, Wu GE, Wu J. Highly conserved cross-reactive CD4+ T-cell HA-epitopes of seasonal and the 2009 pandemic influenza viruses. Influenza Other Respir Viruses 2010; 4:249-58. [PMID: 20716156 PMCID: PMC4634651 DOI: 10.1111/j.1750-2659.2010.00161.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Please cite this paper as: Duvvuri et al. (2010) Highly conserved cross‐reactive CD4+ T‐cell HA‐epitopes of seasonal and the 2009 pandemic influenza viruses. Influenza and Other Respiratory Viruses 4(5), 249–258. Background The relatively mild nature of the 2009 influenza pandemic (nH1N1) highlights the overriding importance of pre‐existing immune memory. The absence of cross‐reactive antibodies to nH1N1 in most individuals suggests that such attenuation may be attributed to pre‐existing cellular immune responses to epitopes shared between nH1N1 virus and previously circulating strains of inter‐pandemic influenza A viruses. Results We sought to identify potential CD4+ T cell epitopes and predict the level of cross‐reactivity of responding T cells. By performing large‐scale major histocompatibility complex II analyses on Hemagglutinin (HA) proteins, we investigated the degree of T‐cell cross‐reactivity between seasonal influenza A (sH1N1, H3N2) from 1968 to 2009 and nH1N1 strains. Each epitope was examined against all the protein sequences that correspond to sH1N1, H3N2, and nH1N1. T‐cell cross‐reactivity was estimated to be 52%, and maximum conservancy was found between sH1N1 and nH1N1 with a significant correlation (P < 0·05). Conclusions Given the importance of cellular responses in kinetics of influenza infection in humans, our findings underscore the role of T‐cell assays for understanding the inter‐pandemic variability in severity and for planning treatment methods for emerging influenza viruses.
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Affiliation(s)
- Venkata R S K Duvvuri
- MITACS Centre for Disease Modeling, York Institute of Health Research, Toronto, Ontario, Canada
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