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Osei I, Mendy E, van Zandvoort K, Jobe O, Sarwar G, Wutor BM, Flasche S, Mohammed NI, Bruce J, Greenwood B, Mackenzie GA. Directly observed social contact patterns among school children in rural Gambia. Epidemics 2024; 49:100790. [PMID: 39270441 DOI: 10.1016/j.epidem.2024.100790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Revised: 09/03/2024] [Accepted: 09/04/2024] [Indexed: 09/15/2024] Open
Abstract
INTRODUCTION School-aged children play a major role in the transmission of many respiratory pathogens due to high rate of close contacts in schools. The validity and accuracy of proxy-reported contact data may be limited, particularly for children when attending school. We observed social contacts within schools and assessed the accuracy of proxy-reported versus observed physical contact data among students in rural Gambia. METHODS We enrolled school children who had also been recruited to a survey of Streptococcus pneumoniae carriage and social contacts. We visited participants at school and observed their contact patterns within and outside the classroom for two hours. We recorded the contact type, gender and approximate age of the contactee, and class size. We calculated age-stratified contact matrices to determine in-school contact patterns. We compared proxy-reported estimated physical contacts for the subset of participants (18 %) randomised to be observed on the same day for which the parent or caregiver reported the school contacts. RESULTS We recorded 3822 contacts for 219 participants from 114 schools. The median number of contacts was 15 (IQR: 11-20). Contact patterns were strongly age-assortative, and mainly involved physical touch (67.5 %). Those aged 5-9 years had the highest mean number of contacts [19.0 (95 %CI: 16.7-21.3)] while the ≥ 15-year age group had fewer contacts [12.8 (95 %CI: 10.9-14.7)]. Forty (18 %) participants had their school-observed contact data collected on the same day as their caregiver reported their estimated physical contacts at school; only 22.5 % had agreement within ±2 contacts between the observed and reported contacts. Fifty-eight percent of proxy-reported contacts were under-estimates. CONCLUSIONS Social contact rates observed among pupils at schools in rural Gambia were high, strongly age-assortative, and physical. Reporting of school contacts by proxies may underestimate the effect of school-age children in modelling studies of transmission of infections. New approaches are needed to quantify contacts within schools.
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Affiliation(s)
- Isaac Osei
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Emmanuel Mendy
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia
| | - Kevin van Zandvoort
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Olimatou Jobe
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia
| | - Golam Sarwar
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia
| | - Baleng Mahama Wutor
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia
| | - Stefan Flasche
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Centre of Global Health, Charite - Universitätsmedizin, Berlin, Germany
| | - Nuredin I Mohammed
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia
| | - Jane Bruce
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Brian Greenwood
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Grant A Mackenzie
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, the Gambia; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK; Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Australia
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Trevisi L, Brooks MB, Becerra MC, Calderón RI, Contreras CC, Galea JT, Jimenez J, Lecca L, Yataco RM, Tovar X, Zhang Z, Murray MB, Huang CC. Who Transmits Tuberculosis to Whom: A Cross-Sectional Analysis of a Cohort Study in Lima, Peru. Am J Respir Crit Care Med 2024; 210:222-233. [PMID: 38416532 PMCID: PMC11276835 DOI: 10.1164/rccm.202307-1217oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 02/27/2024] [Indexed: 02/29/2024] Open
Abstract
Rationale: The persistent burden of tuberculosis (TB) disease emphasizes the need to identify individuals with TB for treatment and those at a high risk of incident TB for prevention. Targeting interventions toward those at high risk of developing and transmitting TB is a public health priority. Objectives: We aimed to identify characteristics of individuals involved in TB transmission in a community setting, which may guide the prioritization of targeted interventions. Methods: We collected clinical and sociodemographic data from a cohort of patients with TB in Lima, Peru. We used whole-genome sequencing data to assess the genetic distance between all possible pairs of patients; we considered pairs to be the result of a direct transmission event if they differed by three or fewer SNPs, and we assumed that the first diagnosed patient in a pair was the transmitter and the second was the recipient. We used logistic regression to examine the association between host factors and the likelihood of direct TB transmission. Measurements and Main Results: Analyzing data from 2,518 index patients with TB, we identified 1,447 direct transmission pairs. Regardless of recipient attributes, individuals less than 34 years old, males, and those with a history of incarceration had a higher likelihood of being transmitters in direct transmission pairs. Direct transmission was more likely when both patients were drinkers or smokers. Conclusions: This study identifies men, young adults, former prisoners, alcohol consumers, and smokers as priority groups for targeted interventions. Innovative strategies are needed to extend TB screening to social groups such as young adults and prisoners with limited access to routine preventive care.
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Affiliation(s)
- Letizia Trevisi
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
| | - Meredith B. Brooks
- Department of Global Health, Boston University School of Public Health, Boston, Massachusetts
| | - Mercedes C. Becerra
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
- Division of Global Health Equity, Brigham and Women’s Hospital, Boston, Massachusetts
| | | | - Carmen C. Contreras
- Socios en Salud, Lima, Peru
- Harvard Global Health Institute, Cambridge, Massachusetts
| | - Jerome T. Galea
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
- College of Behavioral and Community Sciences, School of Social Work, University of South Florida, Tampa, Florida; and
| | | | - Leonid Lecca
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
- Socios en Salud, Lima, Peru
| | | | - Ximena Tovar
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
| | - Zibiao Zhang
- Division of Global Health Equity, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Megan B. Murray
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
- Division of Global Health Equity, Brigham and Women’s Hospital, Boston, Massachusetts
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Chuan-Chin Huang
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts
- Division of Global Health Equity, Brigham and Women’s Hospital, Boston, Massachusetts
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
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Duval A, Leclerc QJ, Guillemot D, Temime L, Opatowski L. An algorithm to build synthetic temporal contact networks based on close-proximity interactions data. PLoS Comput Biol 2024; 20:e1012227. [PMID: 38870216 PMCID: PMC11207132 DOI: 10.1371/journal.pcbi.1012227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 06/26/2024] [Accepted: 06/04/2024] [Indexed: 06/15/2024] Open
Abstract
Small populations (e.g., hospitals, schools or workplaces) are characterised by high contact heterogeneity and stochasticity affecting pathogen transmission dynamics. Empirical individual contact data provide unprecedented information to characterize such heterogeneity and are increasingly available, but are usually collected over a limited period, and can suffer from observation bias. We propose an algorithm to stochastically reconstruct realistic temporal networks from individual contact data in healthcare settings (HCS) and test this approach using real data previously collected in a long-term care facility (LTCF). Our algorithm generates full networks from recorded close-proximity interactions, using hourly inter-individual contact rates and information on individuals' wards, the categories of staff involved in contacts, and the frequency of recurring contacts. It also provides data augmentation by reconstructing contacts for days when some individuals are present in the HCS without having contacts recorded in the empirical data. Recording bias is formalized through an observation model, to allow direct comparison between the augmented and observed networks. We validate our algorithm using data collected during the i-Bird study, and compare the empirical and reconstructed networks. The algorithm was substantially more accurate to reproduce network characteristics than random graphs. The reconstructed networks reproduced well the assortativity by ward (first-third quartiles observed: 0.54-0.64; synthetic: 0.52-0.64) and the hourly staff and patient contact patterns. Importantly, the observed temporal correlation was also well reproduced (0.39-0.50 vs 0.37-0.44), indicating that our algorithm could recreate a realistic temporal structure. The algorithm consistently recreated unobserved contacts to generate full reconstructed networks for the LTCF. To conclude, we propose an approach to generate realistic temporal contact networks and reconstruct unobserved contacts from summary statistics computed using individual-level interaction networks. This could be applied and extended to generate contact networks to other HCS using limited empirical data, to subsequently inform individual-based epidemic models.
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Affiliation(s)
- Audrey Duval
- Institut Pasteur, Université Paris Cité, Epidemiology and Modelling of Bacterial Escape to Antimicrobials (EMEA), Paris, France
- INSERM, Université Paris-Saclay, Université de Versailles St-Quentin-en-Yvelines, Team Echappement aux Anti-infectieux et Pharmacoépidémiologie U1018, CESP, Versailles, France
- Laboratoire Modélisation, Epidémiologie et Surveillance des Risques Sanitaires (MESuRS), Conservatoire National des Arts et Métiers, Paris, France
| | - Quentin J. Leclerc
- Institut Pasteur, Université Paris Cité, Epidemiology and Modelling of Bacterial Escape to Antimicrobials (EMEA), Paris, France
- INSERM, Université Paris-Saclay, Université de Versailles St-Quentin-en-Yvelines, Team Echappement aux Anti-infectieux et Pharmacoépidémiologie U1018, CESP, Versailles, France
- Laboratoire Modélisation, Epidémiologie et Surveillance des Risques Sanitaires (MESuRS), Conservatoire National des Arts et Métiers, Paris, France
| | - Didier Guillemot
- Institut Pasteur, Université Paris Cité, Epidemiology and Modelling of Bacterial Escape to Antimicrobials (EMEA), Paris, France
- INSERM, Université Paris-Saclay, Université de Versailles St-Quentin-en-Yvelines, Team Echappement aux Anti-infectieux et Pharmacoépidémiologie U1018, CESP, Versailles, France
- AP-HP, Paris Saclay, Department of Public Health, Medical Information, Clinical research, Garches, France
| | - Laura Temime
- Laboratoire Modélisation, Epidémiologie et Surveillance des Risques Sanitaires (MESuRS), Conservatoire National des Arts et Métiers, Paris, France
- Institut Pasteur, Conservatoire National des Arts et Métiers, Unité PACRI, Paris, France
| | - Lulla Opatowski
- Institut Pasteur, Université Paris Cité, Epidemiology and Modelling of Bacterial Escape to Antimicrobials (EMEA), Paris, France
- INSERM, Université Paris-Saclay, Université de Versailles St-Quentin-en-Yvelines, Team Echappement aux Anti-infectieux et Pharmacoépidémiologie U1018, CESP, Versailles, France
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Wang M, Wang C, Gui G, Guo F, Zha R, Sun H. Social contacts patterns relevant to the transmission of infectious diseases in Suzhou, China following the COVID-19 epidemic. JOURNAL OF HEALTH, POPULATION, AND NUTRITION 2024; 43:58. [PMID: 38725055 PMCID: PMC11080078 DOI: 10.1186/s41043-024-00555-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 04/27/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND The COVID-19 pandemic has profoundly affected human social contact patterns, but there is limited understanding regarding the post-pandemic social contact patterns. Our objective is to quantitatively assess social contact patterns in Suzhou post-COVID-19. METHODS We employed a diary design and conducted social contact surveys from June to October 2023, utilizing paper questionnaires. A generalized linear model was utilized to analyze the relationship between individual contacts and covariates. We examined the proportions of contact type, location, duration, and frequency. Additionally, age-related mixed matrices were established. RESULTS The participants reported an average of 11.51 (SD 5.96) contact numbers and a total of 19.78 (SD 20.94) contact numbers per day, respectively. The number of contacts was significantly associated with age, household size, and the type of week. Compared to the 0-9 age group, those in the 10-19 age group reported a higher number of contacts (IRR = 1.12, CI: 1.01-1.24), while participants aged 20 and older reported fewer (IRR range: 0.54-0.67). Larger households (5 or more) reported more contacts (IRR = 1.09, CI: 1.01-1.18) and fewer contacts were reported on weekends (IRR = 0.95, CI: 0.90-0.99). School had the highest proportion of contact durations exceeding 4 h (49.5%) and daily frequencies (90.4%), followed by home and workplace. The contact patterns exhibited clear age-assortative mixing, with Q indices of 0.27 and 0.28. CONCLUSIONS We assessed the characteristics of social contact patterns in Suzhou, which are essential for parameterizing models of infectious disease transmission. The high frequency and intensity of contacts among school-aged children should be given special attention, making school intervention policies a crucial component in controlling infectious disease transmission.
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Affiliation(s)
- Mengru Wang
- School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Medical College of Soochow University, Suzhou, Jiangsu, 215123, P.R. China
| | - Congju Wang
- Suzhou High-tech Zone Center for Disease Control and Prevention, Suzhou, 215011, P.R. China
| | - Guoping Gui
- Suzhou High-tech Zone Center for Disease Control and Prevention, Suzhou, 215011, P.R. China
| | - Feng Guo
- Suzhou High-tech Zone Center for Disease Control and Prevention, Suzhou, 215011, P.R. China
| | - Risheng Zha
- Suzhou High-tech Zone Center for Disease Control and Prevention, Suzhou, 215011, P.R. China
| | - Hongpeng Sun
- School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Medical College of Soochow University, Suzhou, Jiangsu, 215123, P.R. China.
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Taube JC, Susswein Z, Colizza V, Bansal S. Respiratory disease contact patterns in the US are stable but heterogeneous. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.26.24306450. [PMID: 38712118 PMCID: PMC11071567 DOI: 10.1101/2024.04.26.24306450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Background Contact plays a critical role in infectious disease transmission. Characterizing heterogeneity in contact patterns across individuals, time, and space is necessary to inform accurate estimates of transmission risk, particularly to explain superspreading, predict age differences in vulnerability, and inform social distancing policies. Current respiratory disease models often rely on data from the 2008 POLYMOD study conducted in Europe, which is now outdated and potentially unrepresentative of behavior in the US. We seek to understand the variation in contact patterns across spatial scales and demographic and social classifications, whether there is seasonality to contact patterns, and what social behavior looks like at baseline in the absence of an ongoing pandemic. Methods We analyze spatiotemporal non-household contact patterns across 11 million survey responses from June 2020 - April 2021 post-stratified on age and gender to correct for sample representation. To characterize spatiotemporal heterogeneity in respiratory contact patterns at the county-week scale, we use generalized additive models. In the absence of pre-pandemic data on contact in the US, we also use a regression approach to produce baseline contact estimates to fill this gap. Findings Although contact patterns varied over time during the pandemic, contact is relatively stable after controlling for disease. We find that the mean number of non-household contacts is spatially heterogeneous regardless of disease. There is additional heterogeneity across age, gender, race/ethnicity, and contact setting, with mean contact decreasing with age and lower in women. The contacts of white individuals and contacts at work or social events change the most under increased national incidence. Interpretation We develop the first county-level estimates of non-pandemic contact rates for the US that can fill critical gaps in parameterizing disease models. Our results identify that spatiotemporal, demographic, and social heterogeneity in contact patterns is highly structured, informing the risk landscape of respiratory disease transmission in the US.
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Affiliation(s)
- Juliana C. Taube
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Zachary Susswein
- Department of Biology, Georgetown University, Washington, DC, USA
| | | | - Shweta Bansal
- Department of Biology, Georgetown University, Washington, DC, USA
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Bekker-Nielsen Dunbar M. Transmission matrices used in epidemiologic modelling. Infect Dis Model 2024; 9:185-194. [PMID: 38249428 PMCID: PMC10796975 DOI: 10.1016/j.idm.2023.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/24/2023] [Accepted: 11/26/2023] [Indexed: 01/23/2024] Open
Abstract
Mixing matrices are included in infectious disease models to reflect transmission opportunities between population strata. These matrices were originally constructed on the basis of theoretical considerations and most of the early work in this area originates from research on sexually transferred diseases in the 80s, in response to AIDS. Later work in the 90s populated these matrices on the basis of survey data gathered to capture transmission risks for respiratory diseases. We provide an overview of developments in the construction of matrices for capturing transmission opportunities in populations. Such transmission matrices are useful for epidemiologic modelling to capture within and between stratum transmission and can be informed from theoretical mixing assumptions, informed by empirical evidence gathered through investigation as well as generated on the basis of data. Links to summary measures and threshold conditions are also provided.
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Affiliation(s)
- M. Bekker-Nielsen Dunbar
- Centre for Research on Pandemics & Society, OsloMet – Oslo Metropolitan University, HG536, Holbergs gate 1, Oslo, 0166, Norway
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Nagpal S, Kumar R, Noronha RF, Kumar S, Gupta D, Amarchand R, Gosain M, Sharma H, Menon GI, Krishnan A. Seasonal variations in social contact patterns in a rural population in north India: Implications for pandemic control. PLoS One 2024; 19:e0296483. [PMID: 38386667 PMCID: PMC10883557 DOI: 10.1371/journal.pone.0296483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 12/11/2023] [Indexed: 02/24/2024] Open
Abstract
Social contact mixing patterns are critical to model the transmission of communicable diseases, and have been employed to model disease outbreaks including COVID-19. Nonetheless, there is a paucity of studies on contact mixing in low and middle-income countries such as India. Furthermore, mathematical models of disease outbreaks do not account for the temporal nature of social contacts. We conducted a longitudinal study of social contacts in rural north India across three seasons and analysed the temporal differences in contact patterns. A contact diary survey was performed across three seasons from October 2015-16, in which participants were queried on the number, duration, and characteristics of contacts that occurred on the previous day. A total of 8,421 responses from 3,052 respondents (49% females) recorded characteristics of 180,073 contacts. Respondents reported a significantly higher number and duration of contacts in the winter, followed by the summer and the monsoon season (Nemenyi post-hoc, p<0.001). Participants aged 0-9 years and 10-19 years of age reported the highest median number of contacts (16 (IQR 12-21), 17 (IQR 13-24) respectively) and were found to have the highest node centrality in the social network of the region (pageranks = 0.20, 0.17). A large proportion (>80%) of contacts that were reported in schools or on public transport involved physical contact. To the best of our knowledge, our study is the first from India to show that contact mixing patterns vary by the time of the year and provides useful implications for pandemic control. We compared the differences in the number, duration and location of contacts by age-group and gender, and studied the impact of the season, age-group, employment and day of the week on the number and duration of contacts using multivariate negative binomial regression. We created a social network to further understand the age and gender-specific contact patterns, and used the contact matrices in each season to parameterise a nine-compartment agent-based model for simulating a COVID-19 epidemic in each season. Our results can be used to parameterize more accurate mathematical models for prediction of epidemiological trends of infections in rural India.
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Affiliation(s)
| | - Rakesh Kumar
- All India Institute of Medical Sciences, New Delhi, India
| | | | - Supriya Kumar
- Bill and Melinda Gates Foundation, Seattle, WA, United States of America
| | | | | | - Mudita Gosain
- All India Institute of Medical Sciences, New Delhi, India
| | | | | | - Anand Krishnan
- All India Institute of Medical Sciences, New Delhi, India
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Are EB, Card KG, Colijn C. The role of vaccine status homophily in the COVID-19 pandemic: a cross-sectional survey with modelling. BMC Public Health 2024; 24:472. [PMID: 38355444 PMCID: PMC10868109 DOI: 10.1186/s12889-024-17957-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 02/01/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Vaccine homophily describes non-heterogeneous vaccine uptake within contact networks. This study was performed to determine observable patterns of vaccine homophily, as well as the impact of vaccine homophily on disease transmission within and between vaccination groups under conditions of high and low vaccine efficacy. METHODS Residents of British Columbia, Canada, aged ≥ 16 years, were recruited via online advertisements between February and March 2022, and provided information about vaccination status, perceived vaccination status of household and non-household contacts, compliance with COVID-19 prevention guidelines, and history of COVID-19. A deterministic mathematical model was used to assess transmission dynamics between vaccine status groups under conditions of high and low vaccine efficacy. RESULTS Vaccine homophily was observed among those with 0, 2, or 3 doses of the vaccine. Greater homophily was observed among those who had more doses of the vaccine (p < 0.0001). Those with fewer vaccine doses had larger contact networks (p < 0.0001), were more likely to report prior COVID-19 (p < 0.0001), and reported lower compliance with COVID-19 prevention guidelines (p < 0.0001). Mathematical modelling showed that vaccine homophily plays a considerable role in epidemic growth under conditions of high and low vaccine efficacy. Furthermore, vaccine homophily contributes to a high force of infection among unvaccinated individuals under conditions of high vaccine efficacy, as well as to an elevated force of infection from unvaccinated to suboptimally vaccinated individuals under conditions of low vaccine efficacy. INTERPRETATION The uneven uptake of COVID-19 vaccines and the nature of the contact network in the population play important roles in shaping COVID-19 transmission dynamics.
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Affiliation(s)
- Elisha B Are
- Mathematics, Simon Fraser University, Burnaby, BC, Canada.
- Pacific Institute On Pathogens, Pandemics and Society (PIPPS), Simon Fraser University, Burnaby, BC, Canada.
| | - Kiffer G Card
- Pacific Institute On Pathogens, Pandemics and Society (PIPPS), Simon Fraser University, Burnaby, BC, Canada
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
- Institute for Social Connection, Victoria, BC, Canada
| | - Caroline Colijn
- Mathematics, Simon Fraser University, Burnaby, BC, Canada
- Pacific Institute On Pathogens, Pandemics and Society (PIPPS), Simon Fraser University, Burnaby, BC, Canada
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Richard DM, Lipsitch M. What's next: using infectious disease mathematical modelling to address health disparities. Int J Epidemiol 2024; 53:dyad180. [PMID: 38145617 PMCID: PMC10859128 DOI: 10.1093/ije/dyad180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 12/14/2023] [Indexed: 12/27/2023] Open
Affiliation(s)
- Danielle M Richard
- Center for Forecasting and Outbreak Analytics, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Marc Lipsitch
- Center for Forecasting and Outbreak Analytics, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Zhang L, Ma C, Duan W, Yuan J, Wu S, Sun Y, Zhang J, Liu J, Wang Q, Liu M. The role of absolute humidity in influenza transmission in Beijing, China: risk assessment and attributable fraction identification. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2024; 34:767-778. [PMID: 36649482 DOI: 10.1080/09603123.2023.2167948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
To assess the impact of absolute humidity on influenza transmission in Beijing from 2014 to 2019, we estimated the influenza transmissibility via the instantaneous reproduction number (Rt), and evaluated its nonlinear exposure-response association and delayed effects with absolute humidity by using the distributed lag nonlinear model (DLNM). Attributable fraction (AF) of Rt due to absolute humidity was calculated. The result showed a significant M-shaped relationship between Rt and absolute humidity. Compared with the effect of high absolute humidity, the low absolute humidity effect was more immediate with the most significant effect observed at lag 6 days. AFs were relatively high for the group aged 15-24 years, and was the lowest for the group aged 0-4 years with low absolute humidity. Therefore, we concluded that the component attributed to the low absolute humidity effect is greater. Young and middle-aged people are more sensitive to low absolute humidity than children and elderly.
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Affiliation(s)
- Li Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Chunna Ma
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Wei Duan
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Jie Yuan
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Shuangsheng Wu
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Ying Sun
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Jiaojiao Zhang
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Jue Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Quanyi Wang
- Institute for Infectious Disease and Endemic Disease Control, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Min Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
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Vynnycky E, Knapp JK, Papadopoulos T, Cutts FT, Hachiya M, Miyano S, Reef SE. Estimates of the global burden of Congenital Rubella Syndrome, 1996-2019. Int J Infect Dis 2023; 137:149-156. [PMID: 37690575 PMCID: PMC10689248 DOI: 10.1016/j.ijid.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/18/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023] Open
Abstract
OBJECTIVES Many countries introduced rubella-containing vaccination (RCV) after 2011, following changes in recommended World Health Organization (WHO) vaccination strategies and external support. We evaluated the impact of these introductions. METHODS We estimated the country-specific, region-specific, and global Congenital Rubella Syndrome (CRS) incidence during 1996-2019 using mathematical modeling, including routine and campaign vaccination coverage and seroprevalence data. RESULTS In 2019, WHO African and Eastern Mediterranean regions had the highest estimated CRS incidence (64 [95% confidence intervals (CI): 24-123] and 27 [95% CI: 4-67] per 100,000 live births respectively), where nearly half of births occur in countries that have introduced RCV. Other regions, where >95% of births occurred in countries that had introduced RCV, had a low estimated CRS incidence (<1 [95% CI: <1 to 8] and <1 [95% CI: <1 to 12] per 100,000 live births in South-East Asia [SEAR] and the Western Pacific [WPR] respectively, and similarly in Europe and the Americas). The estimated number of CRS births globally declined by approximately two-thirds during 2010-2019, from 100,000 (95% CI: 54,000-166,000) to 32,000 (95% CI: 13,000-60,000), representing a 73% reduction since 1996, largely following RCV introductions in WPR and SEAR, where the greatest reductions occurred. CONCLUSIONS Further reductions can occur by introducing RCV in remaining countries and maintaining high RCV coverage.
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Affiliation(s)
- Emilia Vynnycky
- Statistics Modelling and Economics Department, United Kingdom Health Security Agency, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; TB Modelling Group and Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Jennifer K Knapp
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Timos Papadopoulos
- Statistics Modelling and Economics Department, United Kingdom Health Security Agency, London, UK
| | - Felicity T Cutts
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Masahiko Hachiya
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Toyama, Shinjuku-ku, Tokyo, Japan
| | - Shinsuke Miyano
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Toyama, Shinjuku-ku, Tokyo, Japan
| | - Susan E Reef
- Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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12
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Amofa-Sekyi M, Schaap A, Mureithi L, Kosloff B, Cheeba M, Kangololo B, Vermaak R, Paulsen R, Ruperez M, Floyd S, de Haas P, Fidler S, Hayes R, Ayles H, Shanaube K. Prevalence and risk factors of M tuberculosis infection in young people across 14 communities in Zambia and South Africa. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002077. [PMID: 37773934 PMCID: PMC10540968 DOI: 10.1371/journal.pgph.0002077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/31/2023] [Indexed: 10/01/2023]
Abstract
BACKGROUND From 2018-2021 the TB Reduction through Expanded Antiretroviral Treatment and TB Screening (TREATS) project took place in 21 Zambian and South African communities. The TREATS Incidence of TB Infection Cohort Study was conducted in adolescents and young people (AYP), aged 15-24 years in 14 communities. We describe the baseline prevalence and risk factors of Mycobacterium tuberculosis (M. tuberculosis) infection among this cohort and explore the quantitative QFT-Plus interferon gamma (IFN-γ) responses. METHODS AND FINDINGS A random sample of approximately 300 AYP per community were recruited and information on TB/HIV risk factors, TB symptoms and social mixing patterns collected. QuantiFERON TB Gold Plus assay (QFT-Plus) was used to detect M. tuberculosis infection, following manufacturer's instructions. Logistic regression was used to determine factors associated with infection. 5577 eligible AYP were invited to participate across both countries, with 4648 enrolled. QFT-Plus results were available for 4529: 2552(Zambia) and 1977(South Africa). Overall, 47.6% (2156/4529) AYP had positive QFT-Plus results, the prevalence of infection in South Africa being twice that in Zambia (64.7% (1280/1977) vs 34.3% (867/2552) p<0.001). Infection was associated with age, household contact with TB and alcohol in Zambia but showed no associations in South Africa. The antigen tube differential (TB2-TB1>0.6 IU/ml) of the assay at baseline showed no evidence of association with recent TB exposure. CONCLUSION The high prevalence of infection in AYP warrants urgent action to address TB control, especially in South Africa. Further research is required to delineate antigen tube responses of the QFT-Plus assay more precisely to fully realise the benefit of the additional TB2 tube in high TB/HIV burden settings.
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Affiliation(s)
| | - Ab Schaap
- Zambart, University of Zambia School of Medicine, Lusaka, Zambia
- Department of Infectious and Tropical Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Linda Mureithi
- Health Systems Research Unit, Health Systems Trust, Cape Town, South Africa
| | - Barry Kosloff
- Zambart, University of Zambia School of Medicine, Lusaka, Zambia
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Maina Cheeba
- Zambart, University of Zambia School of Medicine, Lusaka, Zambia
| | - Bxyn Kangololo
- Zambart, University of Zambia School of Medicine, Lusaka, Zambia
| | - Redwaan Vermaak
- Health Systems Research Unit, Health Systems Trust, Cape Town, South Africa
| | - Robynn Paulsen
- Health Systems Research Unit, Health Systems Trust, Cape Town, South Africa
| | - Maria Ruperez
- Department of Infectious and Tropical Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sian Floyd
- Department of Infectious and Tropical Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Petra de Haas
- KNCV Tuberculosis Foundation, The Hague, Netherlands
| | - Sarah Fidler
- HIV Trials Unit, Imperial College London, London, United Kingdom
| | - Richard Hayes
- Department of Infectious and Tropical Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Helen Ayles
- Zambart, University of Zambia School of Medicine, Lusaka, Zambia
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kwame Shanaube
- Zambart, University of Zambia School of Medicine, Lusaka, Zambia
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13
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Zhang K, Xia Z, Huang S, Sun GQ, Lv J, Ajelli M, Ejima K, Liu QH. Evaluating the impact of test-trace-isolate for COVID-19 management and alternative strategies. PLoS Comput Biol 2023; 19:e1011423. [PMID: 37656743 PMCID: PMC10501547 DOI: 10.1371/journal.pcbi.1011423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 09/14/2023] [Accepted: 08/09/2023] [Indexed: 09/03/2023] Open
Abstract
There are many contrasting results concerning the effectiveness of Test-Trace-Isolate (TTI) strategies in mitigating SARS-CoV-2 spread. To shed light on this debate, we developed a novel static-temporal multiplex network characterizing both the regular (static) and random (temporal) contact patterns of individuals and a SARS-CoV-2 transmission model calibrated with historical COVID-19 epidemiological data. We estimated that the TTI strategy alone could not control the disease spread: assuming R0 = 2.5, the infection attack rate would be reduced by 24.5%. Increased test capacity and improved contact trace efficiency only slightly improved the effectiveness of the TTI. We thus investigated the effectiveness of the TTI strategy when coupled with reactive social distancing policies. Limiting contacts on the temporal contact layer would be insufficient to control an epidemic and contacts on both layers would need to be limited simultaneously. For example, the infection attack rate would be reduced by 68.1% when the reactive distancing policy disconnects 30% and 50% of contacts on static and temporal layers, respectively. Our findings highlight that, to reduce the overall transmission, it is important to limit contacts regardless of their types in addition to identifying infected individuals through contact tracing, given the substantial proportion of asymptomatic and pre-symptomatic SARS-CoV-2 transmission.
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Affiliation(s)
- Kun Zhang
- College of Computer Science, Sichuan University, Chengdu, China
| | - Zhichu Xia
- Glasgow College, University of Electronic Science and Technology of China, Chengdu, China
| | - Shudong Huang
- College of Computer Science, Sichuan University, Chengdu, China
| | - Gui-Quan Sun
- Department of Mathematics, North University of China, Taiyuan, China
- Complex Systems Research Center, Shanxi University, Taiyuan, China
| | - Jiancheng Lv
- College of Computer Science, Sichuan University, Chengdu, China
| | - Marco Ajelli
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, School of Public Health, Indiana University Bloomington, Bloomington, Indiana, United States of America
| | - Keisuke Ejima
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Quan-Hui Liu
- College of Computer Science, Sichuan University, Chengdu, China
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14
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Jarquin C, Quezada LF, Gobern L, Balsells E, Rondy M. Early impact of COVID-19 vaccination on older populations in four countries of the Americas, 2021. Rev Panam Salud Publica 2023; 47:e122. [PMID: 37564919 PMCID: PMC10408725 DOI: 10.26633/rpsp.2023.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 06/05/2023] [Indexed: 08/12/2023] Open
Abstract
Objective To estimate the early impact of coronavirus disease 2019 (COVID-19) vaccination on cases in older populations in four countries (Chile, Colombia, Guatemala, and the United States of America), and on deaths in Chile and Guatemala. Methods Data were obtained from national databases of confirmed COVID-19 cases and deaths and vaccinations between 1 July 2020 and 31 August 2021. In each country, pre- and post-vaccination incidence ratios were calculated for COVID-19 cases and deaths in prioritized groups (50-59, 60-69, and ≥70 years) compared with those in the reference group (<50 years). Vaccination effect was calculated as the percentage change in incidence ratios between pre- and post-vaccination periods. Results The ratio of COVID-19 cases in those aged ≥50 years to those aged <50 years decreased significantly after vaccine implementation by 9.8% (95% CI: 9.5 to 10.1%) in Chile, 22.5% (95% CI: 22.0 to 23.1%) in Colombia, 20.8% (95% CI: 20.6 to 21.1%) in Guatemala, and 7.8% (95% CI: 7.6 to 7.9%) in the USA. Reductions in the ratio were highest in adults aged ≥70 years. The effect of vaccination on deaths, with time lags incorporated, was highest in the age group ≥70 years in both Chile and Guatemala: 14.4% (95% CI: 11.4 to 17.4%) and 37.3% (95% CI: 30.9 to 43.7%), respectively. Conclusions COVID-19 vaccination significantly reduced morbidity in the early post-vaccination period in targeted groups. In the context of a global pandemic with limited vaccine availability, prioritization strategies are important to reduce the burden of disease in high-risk age groups.
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Affiliation(s)
- Claudia Jarquin
- Pan American Health OrganizationGuatemala CityGuatemalaPan American Health Organization, Guatemala City, Guatemala.
| | - Luis Fernando Quezada
- Pan American Health OrganizationGuatemala CityGuatemalaPan American Health Organization, Guatemala City, Guatemala.
| | - Lorena Gobern
- Ministry of Public Health and Social Assistance of GuatemalaGuatemala CityGuatemalaMinistry of Public Health and Social Assistance of Guatemala, Guatemala City, Guatemala.
| | - Evelyn Balsells
- Pan American Health OrganizationGuatemala CityGuatemalaPan American Health Organization, Guatemala City, Guatemala.
| | - Marc Rondy
- Pan American Health OrganizationGuatemala CityGuatemalaPan American Health Organization, Guatemala City, Guatemala.
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15
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Ahmed A, DeWitt ME, Dantuluri KL, Castri P, Buahin A, LaGarde WH, Weintraub WS, Rossman W, Santos RP, Gibbs M, Uschner D. Characterisation of infection-induced SARS-CoV-2 seroprevalence amongst children and adolescents in North Carolina. Epidemiol Infect 2023; 151:e63. [PMID: 37009915 PMCID: PMC10154644 DOI: 10.1017/s0950268823000481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/15/2023] [Accepted: 03/22/2023] [Indexed: 04/04/2023] Open
Abstract
Few prospective studies have documented the seropositivity among those children infected with severe acute respiratory syndrome coronavirus 2. From 2 April 2021 to 24 June 2021, we prospectively enrolled children between the ages of 2 and 17 years at three North Carolina healthcare systems. Participants received at least four at-home serological tests detecting the presence of antibodies against, but not differentiating between, the nucleocapsid or spike antigen. A total of 1,058 participants were enrolled in the study, completing 2,709 tests between 1 May 2021 and 31 October 2021. Using multilevel regression with poststratification techniques and considering our assay sensitivity and sensitivity, we estimated that the seroprevalence of infection-induced antibodies among unvaccinated children and adolescents aged 2-17 years in North Carolina increased from 15.2% (95% credible interval, CrI 9.0-22.0) in May 2021 to 54.1% (95% CrI 46.7-61.1) by October 2021, indicating an average infection-to-reported-case ratio of 5. A rapid rise in seropositivity was most pronounced in those unvaccinated children aged 12-17 years, based on our estimates. This study underlines the utility of serial, serological testing to inform a broader understanding of the regional immune landscape and spread of infection.
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Affiliation(s)
- Amina Ahmed
- Levine Children’s Hospital, Atrium Health, Charlotte, NC, USA
- Department of Internal Medicine, Section on Infectious Diseases, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Michael E. DeWitt
- Department of Internal Medicine, Section on Infectious Diseases, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | - Paola Castri
- Department of Internal Medicine, Section on Infectious Diseases, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Asare Buahin
- Milken School of Public Health, George Washington University, Washington, DC, USA
| | - William H. LaGarde
- Department of Pediatrics, WakeMed Health and Hospitals, Raleigh, NC, USA
| | - William S. Weintraub
- MedStar Healthcare Delivery Research Network, MedStar Health Research Institute, Washington, DC, USA
- MedStar Healthcare Delivery Research Network, Georgetown University, Washington, DC, USA
| | - Whitney Rossman
- Center for Outcomes Research and Evaluation, Atrium Health, Charlotte, NC, USA
| | | | - Michael Gibbs
- Department of Emergency Medicine, Atrium Health, Charlotte, NC, USA
| | - Diane Uschner
- Milken School of Public Health, George Washington University, Washington, DC, USA
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16
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Tsang TK, Huang X, Wang C, Chen S, Yang B, Cauchemez S, Cowling BJ. The effect of variation of individual infectiousness on SARS-CoV-2 transmission in households. eLife 2023; 12:82611. [PMID: 36880191 PMCID: PMC9991055 DOI: 10.7554/elife.82611] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
Quantifying variation of individual infectiousness is critical to inform disease control. Previous studies reported substantial heterogeneity in transmission of many infectious diseases including SARS-CoV-2. However, those results are difficult to interpret since the number of contacts is rarely considered in such approaches. Here, we analyze data from 17 SARS-CoV-2 household transmission studies conducted in periods dominated by ancestral strains, in which the number of contacts was known. By fitting individual-based household transmission models to these data, accounting for number of contacts and baseline transmission probabilities, the pooled estimate suggests that the 20% most infectious cases have 3.1-fold (95% confidence interval: 2.2- to 4.2-fold) higher infectiousness than average cases, which is consistent with the observed heterogeneity in viral shedding. Household data can inform the estimation of transmission heterogeneity, which is important for epidemic management.
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Affiliation(s)
- Tim K Tsang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
- Laboratory of Data Discovery for HealthHong KongChina
| | - Xiaotong Huang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Can Wang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Sijie Chen
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Bingyi Yang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong KongHong KongChina
| | - Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut PasteurParisFrance
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17
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Rodiah I, Vanella P, Kuhlmann A, Jaeger VK, Harries M, Krause G, Karch A, Bock W, Lange B. Age-specific contribution of contacts to transmission of SARS-CoV-2 in Germany. Eur J Epidemiol 2023; 38:39-58. [PMID: 36593336 PMCID: PMC9807433 DOI: 10.1007/s10654-022-00938-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 10/03/2022] [Indexed: 01/04/2023]
Abstract
Current estimates of pandemic SARS-CoV-2 spread in Germany using infectious disease models often do not use age-specific infection parameters and are not always based on age-specific contact matrices of the population. They also do usually not include setting- or pandemic phase-based information from epidemiological studies of reported cases and do not account for age-specific underdetection of reported cases. Here, we report likely pandemic spread using an age-structured model to understand the age- and setting-specific contribution of contacts to transmission during different phases of the COVID-19 pandemic in Germany. We developed a deterministic SEIRS model using a pre-pandemic contact matrix. The model was optimized to fit age-specific SARS-CoV-2 incidences reported by the German National Public Health Institute (Robert Koch Institute), includes information on setting-specific reported cases in schools and integrates age- and pandemic period-specific parameters for underdetection of reported cases deduced from a large population-based seroprevalence studies. Taking age-specific underreporting into account, younger adults and teenagers were identified in the modeling study as relevant contributors to infections during the first three pandemic waves in Germany. For the fifth wave, the Delta to Omicron transition, only age-specific parametrization reproduces the observed relative and absolute increase in pediatric hospitalizations in Germany. Taking into account age-specific underdetection did not change considerably how much contacts in schools contributed to the total burden of infection in the population (up to 12% with open schools under hygiene measures in the third wave). Accounting for the pandemic phase and age-specific underreporting is important to correctly identify those groups of the population in which quarantine, testing, vaccination, and contact-reduction measures are likely to be most effective and efficient. Age-specific parametrization is also highly relevant to generate informative age-specific output for decision makers and resource planers.
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Affiliation(s)
- Isti Rodiah
- Department of Epidemiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, DE-38124, Brunswick, Germany.
- German Centre for Infection Research (DZIF), Inhoffenstr. 7, DE-38124, Brunswick, Germany.
| | - Patrizio Vanella
- Department of Epidemiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, DE-38124, Brunswick, Germany
- Chair of Empirical Methods in Social Science and Demography, University of Rostock, Ulmenstr. 69, DE-18057, Rostock, Germany
| | - Alexander Kuhlmann
- Faculty of Medicine, Martin Luther University Halle-Wittenberg, Magdeburgerstr. 8, DE-06112, Halle (Saale), Germany
- German Center for Lung Research (DZL), Biomedical Research in End-Stage and Obstructive Lung Disease Hannover (BREATH), Carl-Neuberg-Str. 1, DE-30625, Hannover, Germany
| | - Veronika K Jaeger
- Institute of Epidemiology and Social Medicine, University of Münster, Albert-Schweitzer-Campus 1, DE-48149, Münster, Germany
| | - Manuela Harries
- Department of Epidemiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, DE-38124, Brunswick, Germany
- German Centre for Infection Research (DZIF), Inhoffenstr. 7, DE-38124, Brunswick, Germany
| | - Gerard Krause
- Department of Epidemiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, DE-38124, Brunswick, Germany
- German Centre for Infection Research (DZIF), Inhoffenstr. 7, DE-38124, Brunswick, Germany
| | - Andre Karch
- Institute of Epidemiology and Social Medicine, University of Münster, Albert-Schweitzer-Campus 1, DE-48149, Münster, Germany
| | - Wolfgang Bock
- Technomathematics Group, Department of Mathematics, TU Kaiserslautern, Gottlieb-Daimler-Straße 48, DE-67663, Kaiserslautern, Germany
| | - Berit Lange
- Department of Epidemiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, DE-38124, Brunswick, Germany.
- German Centre for Infection Research (DZIF), Inhoffenstr. 7, DE-38124, Brunswick, Germany.
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18
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Combination of Cetylpyridinium Chloride and Chlorhexidine Acetate: A Promising Candidate for Rapid Killing of Gram-Positive/Gram-Negative Bacteria and Fungi. Curr Microbiol 2023; 80:97. [PMID: 36738393 PMCID: PMC9899061 DOI: 10.1007/s00284-023-03198-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/19/2023] [Indexed: 02/05/2023]
Abstract
Combined use of the present antimicrobial drugs has been proved to be an alternative approach for antimicrobial agents' development since the co-existed of the drugs working in different mechanism have been demonstrated potentially enhance their antimicrobial activity. In this work, antibacterial and antifungal activity of the cetylpyridinium chloride (CPC)/chlorhexidine acetate (CHA) combination was evaluated for the first time, while a universal concentration for the rapid killing of gram-positive/gram-negative bacteria and fungi was also proposed. The minimum inhibitory concentrations (MIC) of CPC and CHA used alone or in combination were first measured, showing that the combined treatment decreased the MIC against tested gram-positive/gram-negative bacteria and fungi to 1/8-1/2. Growth curve assays demonstrated CPC and CHA had dynamic combined effects against the tested microorganisms at the concentration equal to MIC. Besides, combined use of these two drugs could also enhance their biocidal activity, which was illustrated by fluorescence microscopy and SEM images, as well as soluble protein measurement. More importantly, in vitro acute eye and skin irritation tests showed short-term contact with CPC/CHA combination would not cause any damage to mammalian mucosa and skin. In a word, CPC/CHA combination exhibited broad-spectrum antibacterial and antifungal activity against tested gram-positive/gram-negative bacteria and fungi while without any acute irritation to mammalian mucosa and skin, providing a new perspective on the selection of personal disinfectants.
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19
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Hoxha I, Agahi R, Bimbashi A, Aliu M, Raka L, Bajraktari I, Beqiri P, Adams LV. Higher COVID-19 Vaccination Rates Are Associated with Lower COVID-19 Mortality: A Global Analysis. Vaccines (Basel) 2022; 11:74. [PMID: 36679919 PMCID: PMC9862920 DOI: 10.3390/vaccines11010074] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/24/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
Mass vaccination initiatives are underway worldwide, and a considerable percentage of the world's population is now vaccinated. This study examined the association of COVID-19 deaths per 1000 cases with a fully vaccinated population. The global median deaths per 1000 cases were 15.68 (IQR 9.84, 25.87) after 6 months of vaccinations and 11.96 (IQR 6.08, 20.63) after 12 months. Across 164 countries, we found significant variations in vaccination levels of populations, booster doses, and mortality, with higher vaccine coverage and lower mortality in high-income countries. Several regression models were performed to test the association between vaccination and COVID-19 mortality. Control variables were used to account for confounding variables. A 10-percentage-point increase in vaccination was associated with an 18.1% decrease in mortality after 6 months (95%CI, 7.4-28.8%) and a 16.8% decrease after 12 months (95%CI, 6.9-26.7%). A 10-percentage-point increase in booster vaccination rates was associated with a 33.1% decrease in COVID-19 mortality (95%CI, 16.0-50.2%). This relationship is present in most analyses by country income groups with variations in the effect size. Efforts are needed to reduce vaccine hesitancy while ensuring suitable infrastructure and supply to enable all countries to increase their vaccination rates.
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Affiliation(s)
- Ilir Hoxha
- The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, NH 03766, USA
- Research Unit, Heimerer College, 10000 Prishtina, Kosovo
- Evidence Synthesis Group, 10000 Prishtina, Kosovo
| | - Riaz Agahi
- Research Unit, Heimerer College, 10000 Prishtina, Kosovo
| | | | - Mrika Aliu
- The Dartmouth Institute for Health Policy and Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, NH 03766, USA
| | - Lul Raka
- Faculty of Medicine, University of Prishtina, 10000 Prishtina, Kosovo
| | - Ilirjana Bajraktari
- Research Unit, Heimerer College, 10000 Prishtina, Kosovo
- European Group on Health Care Delivery, 55305 Jonkoping, Sweden
| | - Petrit Beqiri
- Research Unit, Heimerer College, 10000 Prishtina, Kosovo
- Institute for Health and Nursing Science, Faculty of Medicine, Martin Luther University Halle-Wittenberg, 06108 Halle (Saale), Germany
| | - Lisa V. Adams
- Centre for Global Health Equity, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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20
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Breen CF, Mahmud AS, Feehan DM. Novel estimates reveal subnational heterogeneities in disease-relevant contact patterns in the United States. PLoS Comput Biol 2022; 18:e1010742. [PMID: 36459512 PMCID: PMC9749998 DOI: 10.1371/journal.pcbi.1010742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 12/14/2022] [Accepted: 11/16/2022] [Indexed: 12/04/2022] Open
Abstract
Population contact patterns fundamentally determine the spread of directly transmitted airborne pathogens such as SARS-CoV-2 and influenza. Reliable quantitative estimates of contact patterns are therefore critical to modeling and reducing the spread of directly transmitted infectious diseases and to assessing the effectiveness of interventions intended to limit risky contacts. While many countries have used surveys and contact diaries to collect national-level contact data, local-level estimates of age-specific contact patterns remain rare. Yet, these local-level data are critical since disease dynamics and public health policy typically vary by geography. To overcome this challenge, we introduce a flexible model that can estimate age-specific contact patterns at the subnational level by combining national-level interpersonal contact data with other locality-specific data sources using multilevel regression with poststratification (MRP). We estimate daily contact matrices for all 50 US states and Washington DC from April 2020 to May 2021 using national contact data from the US. Our results reveal important state-level heterogeneities in levels and trends of contacts across the US over the course of the COVID-19 pandemic, with implications for the spread of respiratory diseases.
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Affiliation(s)
- Casey F. Breen
- Department of Demography, University of California, Berkeley, Berkeley, California, United States of America
| | - Ayesha S. Mahmud
- Department of Demography, University of California, Berkeley, Berkeley, California, United States of America
| | - Dennis M. Feehan
- Department of Demography, University of California, Berkeley, Berkeley, California, United States of America
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21
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Migliara G, Renzi E, Baccolini V, Cerri A, Donia P, Massimi A, Marzuillo C, De Vito C, Casini L, Polimeni A, Gaudio E, Villari P. Predictors of SARS-CoV-2 Infection in University Students: A Case-Control Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:14376. [PMID: 36361257 PMCID: PMC9655450 DOI: 10.3390/ijerph192114376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 10/30/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
Closure of Higher Education Institutions in the early phase of the SARS-CoV-2 pandemic was largely diffused. With their reopening, numerous preventive measures have been enacted, but limited evidence exists on students' behavior that could influence their infection risk. We conducted a case-control study at the Sapienza University of Rome to identify protective and risk factors for SARS-CoV-2 infection. Students attending the campus within 48 h of SARS-CoV-2 infection were considered cases. Controls were students who come in contact with a confirmed case within the campus. Demographic features and activities carried out before positivity or contact were investigated. Multivariable logistic regression models were built to identify factors associated with SARS-CoV-2 infection, estimating adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). The analysis showed an increased risk of SARS-CoV-2 infection for attending the second year or above of university (aOR 17.7, 95% CI 2.21-142.82) and participating in private parties or ceremonies (aOR 15.9, 95% CI 2.30-109.67) while living outside the family (aOR 0.08, 95% CI 0.01-0.54) and attending practical activities or libraries on campus (aOR 0.29, 95% CI 0.08-0.97) reduced the risk. Data strongly suggests that it may be safe to participate in activities organized under strict infection prevention guidelines. Tailored prevention measures might reduce the risk of infection in university students.
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Affiliation(s)
- Giuseppe Migliara
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Erika Renzi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Valentina Baccolini
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Ambrogio Cerri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Pierluigi Donia
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Azzurra Massimi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Carolina Marzuillo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Corrado De Vito
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Leandro Casini
- Special Office for Prevention, Protection and High Vigilance, Sapienza University of Rome, 00185 Rome, Italy
| | - Antonella Polimeni
- Department of Oral and Maxillofacial Science, Sapienza University of Rome, 00185 Rome, Italy
| | - Eugenio Gaudio
- Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Paolo Villari
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
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22
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Bekker‐Nielsen Dunbar M, Hofmann F, Held L. Assessing the effect of school closures on the spread of COVID-19 in Zurich. JOURNAL OF THE ROYAL STATISTICAL SOCIETY. SERIES A, (STATISTICS IN SOCIETY) 2022; 185:S131-S142. [PMID: 38607867 PMCID: PMC9878126 DOI: 10.1111/rssa.12910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 04/08/2022] [Indexed: 04/14/2024]
Abstract
The effect of school closure on the spread of COVID-19 has been discussed intensively in the literature and the news. To capture the interdependencies between children and adults, we consider daily age-stratified incidence data and contact patterns between age groups which change over time to reflect social distancing policy indicators. We fit a multivariate time-series endemic-epidemic model to such data from the Canton of Zurich, Switzerland and use the model to predict the age-specific incidence in a counterfactual approach (with and without school closures). The results indicate a 17% median increase of incidence in the youngest age group (0-14 year olds), whereas the relative increase in the other age groups drops to values between 2% and 3%. We argue that our approach is more informative to policy makers than summarising the effect of school closures with time-dependent effective reproduction numbers, which are difficult to estimate due to the sparsity of incidence counts within the relevant age groups.
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Affiliation(s)
| | - Felix Hofmann
- Epidemiology, Biostatistics and Prevention Institute (EBPI)University of Zurich (UZH)ZurichSwitzerland
| | - Leonhard Held
- Epidemiology, Biostatistics and Prevention Institute (EBPI)University of Zurich (UZH)ZurichSwitzerland
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23
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Vinceti M, Balboni E, Rothman KJ, Teggi S, Bellino S, Pezzotti P, Ferrari F, Orsini N, Filippini T. Substantial impact of mobility restrictions on reducing COVID-19 incidence in Italy in 2020. J Travel Med 2022; 29:6649390. [PMID: 35876268 PMCID: PMC9384467 DOI: 10.1093/jtm/taac081] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/06/2022] [Accepted: 07/18/2022] [Indexed: 11/12/2022]
Abstract
BACKGROUND Italy was the first country after China to be severely affected by the COVID-19 pandemic, in early 2020. The country responded swiftly to the outbreak with a nationwide two-step lockdown, the first one light and the second one tight. By analyzing 2020 national mobile phone movements, we assessed how lockdown compliance influenced its efficacy. METHODS We measured individual mobility during the first epidemic wave with mobile phone movements tracked through carrier networks, and related this mobility to daily new SARS-CoV-2 infections, hospital admissions, intensive care admissions and deaths attributed to COVID-19, taking into account reason for travel (work-related or not) and the means of transport. RESULTS The tight lockdown resulted in an 82% reduction in mobility for the entire country and was effective in swiftly curbing the outbreak as indicated by a shorter time-to-peak of all health outcomes, particularly for provinces with the highest mobility reductions and the most intense COVID-19 spread. Reduction of work-related mobility was accompanied by a nearly linear benefit in outbreak containment; work-unrelated movements had a similar effect only for restrictions exceeding 50%. Reduction in mobility by car and by airplane was nearly linearly associated with a decrease in most COVID-19 health outcomes, while for train travel reductions exceeding 55% had no additional beneficial effects. The absence of viral variants and vaccine availability during the study period eliminated confounding from these two sources. CONCLUSIONS Adherence to the COVID-19 tight lockdown during the first wave in Italy was high and effective in curtailing the outbreak. Any work-related mobility reduction was effective, but only high reductions in work-unrelated mobility restrictions were effective. For train travel, there was a threshold above which no further benefit occurred. These findings could be particular to the spread of SARS-CoV-2, but might also apply to other communicable infections with comparable transmission dynamics.
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Affiliation(s)
- Marco Vinceti
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA
| | - Erica Balboni
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Kenneth J Rothman
- Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA.,RTI Health Solutions, Research Triangle Park, NC 27709, USA
| | - Sergio Teggi
- Department of Engineering 'Enzo Ferrari', University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Stefania Bellino
- Department of Infectious Diseases, Italian National Institute of Health, 00161 Rome, Italy
| | - Patrizio Pezzotti
- Department of Infectious Diseases, Italian National Institute of Health, 00161 Rome, Italy
| | | | - Nicola Orsini
- Department of Global Public Health, Karolinska Institute, Stockholm, 11365 Stockholm, Sweden
| | - Tommaso Filippini
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.,School of Public Health, University of California Berkeley, 1995 University Avenue, Berkeley, CA 94704, USA
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24
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Trentini F, Manna A, Balbo N, Marziano V, Guzzetta G, O’Dell S, Kummer AG, Litvinova M, Merler S, Ajelli M, Poletti P, Melegaro A. Investigating the relationship between interventions, contact patterns, and SARS-CoV-2 transmissibility. Epidemics 2022; 40:100601. [PMID: 35772295 PMCID: PMC9212945 DOI: 10.1016/j.epidem.2022.100601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND After a rapid upsurge of COVID-19 cases in Italy during the fall of 2020, the government introduced a three-tiered restriction system aimed at increasing physical distancing. The Ministry of Health, after periodic epidemiological risk assessments, assigned a tier to each of the 21 Italian regions and autonomous provinces. It is still unclear to what extent these different sets of measures altered the number of daily interactions and the social mixing patterns. METHODS AND FINDINGS We conducted a survey between July 2020 and March 2021 to monitor changes in social contact patterns among individuals in the metropolitan city of Milan, Italy, which was hardly hit by the second wave of the COVID-19 pandemic. The number of daily contacts during periods characterized by different levels of restrictions was analyzed through negative binomial regression models and age-specific contact matrices were estimated under the different tiers of restrictions. By relying on the empirically estimated mixing patterns, we quantified relative changes in SARS-CoV-2 transmission potential associated with the different tiers. As tighter restrictions were implemented during the fall of 2020, a progressive reduction in the mean number of daily contacts recorded by study participants was observed: from 15.9 % under mild restrictions (yellow tier), to 41.8 % under strong restrictions (red tier). Higher restrictions levels were also found to increase the relative contribution of contacts occurring within the household. The SARS-CoV-2 reproduction number was estimated to decrease by 17.1 % (95 %CI: 1.5-30.1), 25.1 % (95 %CI: 13.0-36.0) and 44.7 % (95 %CI: 33.9-53.0) under the yellow, orange, and red tiers, respectively. CONCLUSIONS Our results give an important quantification of the expected contribution of different restriction levels in shaping social contacts and decreasing the transmission potential of SARS-CoV-2. These estimates can find an operational use in anticipating the effect that the implementation of these tiered restriction can have on SARS-CoV-2 reproduction number under an evolving epidemiological situation.
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Affiliation(s)
- Filippo Trentini
- Dondena Centre for Research on Social Dynamics and Public Policy, Bocconi University, Milan, Italy,Covid Crisis Lab, Bocconi University, Italy,Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy,Correspondence to: Dondena Centre for Research on Social Dynamics and Public Policy, Bocconi University, Via Roentgen 1, 20141 Milan, Italy
| | - Adriana Manna
- Dondena Centre for Research on Social Dynamics and Public Policy, Bocconi University, Milan, Italy,Department of Network and Data Science, Central European University, Wien, Austria
| | - Nicoletta Balbo
- Dondena Centre for Research on Social Dynamics and Public Policy, Bocconi University, Milan, Italy,Department of Social and Political Sciences, Bocconi University, Milan, Italy
| | | | - Giorgio Guzzetta
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Samantha O’Dell
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Allisandra G. Kummer
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Maria Litvinova
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Stefano Merler
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Marco Ajelli
- Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Piero Poletti
- Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | - Alessia Melegaro
- Dondena Centre for Research on Social Dynamics and Public Policy, Bocconi University, Milan, Italy,Covid Crisis Lab, Bocconi University, Italy,Department of Social and Political Sciences, Bocconi University, Milan, Italy,Corresponding author at: Department of Social and Political Sciences, Bocconi University, Milan, Italy
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25
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Thindwa D, Jambo KC, Ojal J, MacPherson P, Dennis Phiri M, Pinsent A, Khundi M, Chiume L, Gallagher KE, Heyderman RS, Corbett EL, French N, Flasche S. Social mixing patterns relevant to infectious diseases spread by close contact in urban Blantyre, Malawi. Epidemics 2022; 40:100590. [PMID: 35691100 PMCID: PMC9176177 DOI: 10.1016/j.epidem.2022.100590] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 05/08/2022] [Accepted: 05/30/2022] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION Understanding human mixing patterns relevant to infectious diseases spread through close contact is vital for modelling transmission dynamics and optimisation of disease control strategies. Mixing patterns in low-income countries like Malawi are not well known. METHODOLOGY We conducted a social mixing survey in urban Blantyre, Malawi between April and July 2021 (between the 2nd and 3rd wave of COVID-19 infections). Participants living in densely-populated neighbourhoods were randomly sampled and, if they consented, reported their physical and non-physical contacts within and outside homes lasting at least 5 min during the previous day. Age-specific mixing rates were calculated, and a negative binomial mixed effects model was used to estimate determinants of contact behaviour. RESULTS Of 1201 individuals enroled, 702 (58.5%) were female, the median age was 15 years (interquartile range [IQR] 5-32) and 127 (10.6%) were HIV-positive. On average, participants reported 10.3 contacts per day (range: 1-25). Mixing patterns were highly age-assortative, particularly those within the community and with skin-to-skin contact. Adults aged 20-49 y reported the most contacts (median:11, IQR: 8-15) of all age groups; 38% (95%CI: 16-63) more than infants (median: 8, IQR: 5-10), who had the least contacts. Household contact frequency increased by 3% (95%CI: 2-5) per additional household member. Unemployed participants had 15% (95%CI: 9-21) fewer contacts than other adults. Among long range (>30 m away from home) contacts, secondary school children had the largest median contact distance from home (257 m, IQR 78-761). HIV-positive status in adults >=18 years-old was not associated with changed contact patterns (rate ratio: 1.01, 95%CI: (0.91-1.12)). During this period of relatively low COVID-19 incidence in Malawi, 301 (25.1%) individuals stated that they had limited their contact with others due to COVID-19 precautions; however, their reported contacts were 8% (95%CI: 1-13) higher. CONCLUSION In urban Malawi, contact rates, are high and age-assortative, with little reported behavioural change due to either HIV-status or COVID-19 circulation. This highlights the limits of contact-restriction-based mitigation strategies in such settings and the need for pandemic preparedness to better understand how contact reductions can be enabled and motivated.
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Affiliation(s)
- Deus Thindwa
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK; Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi.
| | - Kondwani C Jambo
- Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - John Ojal
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK; KEMRI-Wellcome Research Programme, Geographic Medicine Centre, Kilifi, Kenya
| | - Peter MacPherson
- Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
| | - Mphatso Dennis Phiri
- Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - McEwen Khundi
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK; Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi
| | - Lingstone Chiume
- Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi
| | - Katherine E Gallagher
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK; KEMRI-Wellcome Research Programme, Geographic Medicine Centre, Kilifi, Kenya
| | - Robert S Heyderman
- NIHR Global Health Research Unit on Mucosal Pathogens, Research Department of Infection, Division of Infection and Immunity, University College London, London, UK
| | - Elizabeth L Corbett
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
| | - Neil French
- Malawi-Liverpool-Wellcome Clinical Research Programme, Blantyre, Malawi; Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, UK
| | - Stefan Flasche
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, UK; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
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26
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Ringa N, Iyaniwura SA, David S, Irvine MA, Adu P, Spencer M, Janjua NZ, Otterstatter MC. Social Contacts and Transmission of COVID-19 in British Columbia, Canada. Front Public Health 2022; 10:867425. [PMID: 35592086 PMCID: PMC9110764 DOI: 10.3389/fpubh.2022.867425] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/25/2022] [Indexed: 01/08/2023] Open
Abstract
Background Close-contact rates are thought to be a driving force behind the transmission of many infectious respiratory diseases. Yet, contact rates and their relation to transmission and the impact of control measures, are seldom quantified. We quantify the response of contact rates, reported cases and transmission of COVID-19, to public health contact-restriction orders, and examine the associations among these three variables in the province of British Columbia, Canada. Methods We derived time series data for contact rates, daily cases and transmission of COVID-19 from a social contacts survey, reported case counts and by fitting a transmission model to reported cases, respectively. We used segmented regression to investigate impacts of public health orders; Pearson correlation to determine associations between contact rates and transmission; and vector autoregressive modeling to quantify lagged associations between contacts rates, daily cases, and transmission. Results Declines in contact rates and transmission occurred concurrently with the announcement of public health orders, whereas declines in cases showed a reporting delay of about 2 weeks. Contact rates were a significant driver of COVID-19 and explained roughly 19 and 20% of the variation in new cases and transmission, respectively. Interestingly, increases in COVID-19 transmission and cases were followed by reduced contact rates: overall, daily cases explained about 10% of the variation in subsequent contact rates. Conclusion We showed that close-contact rates were a significant time-series driver of transmission and ultimately of reported cases of COVID-19 in British Columbia, Canada and that they varied in response to public health orders. Our results also suggest possible behavioral feedback, by which increased reported cases lead to reduced subsequent contact rates. Our findings help to explain and validate the commonly assumed, but rarely measured, response of close contact rates to public health guidelines and their impact on the dynamics of infectious diseases.
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Affiliation(s)
- Notice Ringa
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | - Sarafa A. Iyaniwura
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- Department of Mathematics, Institute of Applied Mathematics, University of British Columbia, Vancouver, BC, Canada
| | - Samara David
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
| | - Mike A. Irvine
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Prince Adu
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | - Michelle Spencer
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
| | - Naveed Z. Janjua
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
| | - Michael C. Otterstatter
- Data and Analytic Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
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27
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Weerasuriya CK, Harris RC, McQuaid CF, Gomez GB, White RG. Updating age-specific contact structures to match evolving demography in a dynamic mathematical model of tuberculosis vaccination. PLoS Comput Biol 2022; 18:e1010002. [PMID: 35452459 PMCID: PMC9067655 DOI: 10.1371/journal.pcbi.1010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 05/04/2022] [Accepted: 03/08/2022] [Indexed: 11/18/2022] Open
Abstract
We investigated the effects of updating age-specific social contact matrices to match evolving demography on vaccine impact estimates. We used a dynamic transmission model of tuberculosis in India as a case study. We modelled four incremental methods to update contact matrices over time, where each method incorporated its predecessor: fixed contact matrix (M0), preserved contact reciprocity (M1), preserved contact assortativity (M2), and preserved average contacts per individual (M3). We updated the contact matrices of a deterministic compartmental model of tuberculosis transmission, calibrated to epidemiologic data between 2000 and 2019 derived from India. We additionally calibrated the M0, M2, and M3 models to the 2050 TB incidence rate projected by the calibrated M1 model. We stratified age into three groups, children (<15y), adults (≥15y, <65y), and the elderly (≥65y), using World Population Prospects demographic data, between which we applied POLYMOD-derived social contact matrices. We simulated an M72-AS01E-like tuberculosis vaccine delivered from 2027 and estimated the per cent TB incidence rate reduction (IRR) in 2050 under each update method. We found that vaccine impact estimates in all age groups remained relatively stable between the M0–M3 models, irrespective of vaccine-targeting by age group. The maximum difference in impact, observed following adult-targeted vaccination, was 7% in the elderly, in whom we observed IRRs of 19% (uncertainty range 13–32), 20% (UR 13–31), 22% (UR 14–37), and 26% (UR 18–38) following M0, M1, M2 and M3 updates, respectively. We found that model-based TB vaccine impact estimates were relatively insensitive to demography-matched contact matrix updates in an India-like demographic and epidemiologic scenario. Current model-based TB vaccine impact estimates may be reasonably robust to the lack of contact matrix updates, but further research is needed to confirm and generalise this finding. Mathematical models are increasingly used to predict the impact of new and existing tools, e.g., vaccines, that aim to control the transmission of infectious diseases. Within these models, investigators often assume that individuals contact each other according to specific patterns, particularly between and within different age groups. These patterns are typically derived from surveys of social contact or other models and reflect the particular age composition of their source population. However, when models are set over long time scales, e.g., decades, population age composition is likely to change. Despite this reality, few models update their contact patterns to match changing age composition. Furthermore, none have assessed whether their final estimates of disease-control intervention impact are affected by updating contact patterns. We measured whether different techniques to update social contact patterns to match evolving demography produce different vaccine impact estimates, using a mathematical model of tuberculosis set in an India-like scenario between 2025–2050. We found that vaccine impact was stable across a range of different update methods. Thus, existing model-based vaccine impact estimates may be stable to a lack of these updates, but further work is required to confirm these findings.
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Affiliation(s)
- Chathika Krishan Weerasuriya
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Rebecca Claire Harris
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher Finn McQuaid
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gabriela B. Gomez
- Department of Global Health & Development, Faculty of Public Health & Policy, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Richard G. White
- TB Modelling Group, TB Centre and Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
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