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Alarid-Escudero F, Andrews JR, Goldhaber-Fiebert JD. Effects of Mitigation and Control Policies in Realistic Epidemic Models Accounting for Household Transmission Dynamics. Med Decis Making 2024; 44:5-17. [PMID: 37953597 DOI: 10.1177/0272989x231205565] [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] [Indexed: 11/14/2023]
Abstract
BACKGROUND Compartmental infectious disease (ID) models are often used to evaluate nonpharmaceutical interventions (NPIs) and vaccines. Such models rarely separate within-household and community transmission, potentially introducing biases in situations in which multiple transmission routes exist. We formulated an approach that incorporates household structure into ID models, extending the work of House and Keeling. DESIGN We developed a multicompartment susceptible-exposed-infectious-recovered-susceptible-vaccinated (MC-SEIRSV) modeling framework, allowing nonexponentially distributed duration in exposed and infectious compartments, that tracks within-household and community transmission. We simulated epidemics that varied by community and household transmission rates, waning immunity rate, household size (3 or 5 members), and numbers of exposed and infectious compartments (1-3 each). We calibrated otherwise identical models without household structure to the early phase of each parameter combination's epidemic curve. We compared each model pair in terms of epidemic forecasts and predicted NPI and vaccine impacts on the timing and magnitude of the epidemic peak and its total size. Meta-analytic regressions characterized the relationship between household structure inclusion and the size and direction of biases. RESULTS Otherwise similar models with and without household structure produced equivalent early epidemic curves. However, forecasts from models without household structure were biased. Without intervention, they were upward biased on peak size and total epidemic size, with biases also depending on the number of exposed and infectious compartments. Model-estimated NPI effects of a 60% reduction in community contacts on peak time and size were systematically overestimated without household structure. Biases were smaller with a 20% reduction NPI. Because vaccination affected both community and household transmission, their biases were smaller. CONCLUSIONS ID models without household structure can produce biased outcomes in settings in which within-household and community transmission differ. HIGHLIGHTS Infectious disease models rarely separate household transmission from community transmission. The pace of household transmission may differ from community transmission, depends on household size, and can accelerate epidemic growth.Many infectious disease models assume exponential duration distributions for infected states. However, the duration of most infections is not exponentially distributed, and distributional choice alters modeled epidemic dynamics and intervention effectiveness.We propose a mathematical framework for household and community transmission that allows for nonexponential duration times and a suite of interventions and quantified the effect of accounting for household transmission by varying household size and duration distributions of infected states on modeled epidemic dynamics.Failure to include household structure induces biases in the modeled overall course of an epidemic and the effects of interventions delivered differentially in community settings. Epidemic dynamics are faster and more intense in populations with larger household sizes and for diseases with nonexponentially distributed infectious durations. Modelers should consider explicitly incorporating household structure to quantify the effects of non-pharmaceutical interventions (e.g., shelter-in-place).
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Affiliation(s)
- Fernando Alarid-Escudero
- Department of Health Policy, School of Medicine, Stanford University, Stanford, CA, USA
- Center for Health Policy, Freeman Spogli Institute, Stanford University, Stanford, CA, USA
| | - Jason R Andrews
- Department of Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Jeremy D Goldhaber-Fiebert
- Department of Health Policy, School of Medicine, Stanford University, Stanford, CA, USA
- Center for Health Policy, Freeman Spogli Institute, Stanford University, Stanford, CA, USA
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Nikolaou E, German EL, Howard A, Nabwera HM, Matope A, Robinson R, Shiham F, Liatsikos K, McNamara C, Kattera S, Carter K, Parry CM, Read JM, Allen SJ, Urban BC, Hawcutt DB, Hill H, Collins AM, Ferreira DM. Assessing the use of minimally invasive self-sampling at home for long-term monitoring of the microbiota within UK families. Sci Rep 2023; 13:18201. [PMID: 37875557 PMCID: PMC10598218 DOI: 10.1038/s41598-023-45574-6] [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: 06/09/2023] [Accepted: 10/21/2023] [Indexed: 10/26/2023] Open
Abstract
Monitoring the presence of commensal and pathogenic respiratory microorganisms is of critical global importance. However, community-based surveillance is difficult because nasopharyngeal swabs are uncomfortable and painful for a wide age range of participants. We designed a methodology for minimally invasive self-sampling at home and assessed its use for longitudinal monitoring of the oral, nasal and hand microbiota of adults and children within families. Healthy families with two adults and up to three children, living in and near Liverpool, United Kingdom, self-collected saliva, nasal lining fluid using synthetic absorptive matrices and hand swabs at home every two weeks for six months. Questionnaires were used to collect demographic and epidemiological data and assess feasibility and acceptability. Participants were invited to take part in an exit interview. Thirty-three families completed the study. Sampling using our approach was acceptable to 25/33 (76%) families, as sampling was fast (76%), easy (76%) and painless (60%). Saliva and hand sampling was acceptable to all participants of any age, whereas nasal sampling was accepted mostly by adults and children older than 5 years. Multi-niche self-sampling at home can be used by adults and children for longitudinal surveillance of respiratory microorganisms, providing key data for design of future studies.
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Affiliation(s)
- E Nikolaou
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.
- Infection and Immunity, Murdoch Children's Research Institute, Parkville, VIC, 3050, Australia.
- Microbiology and Immunology Department, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, VIC, Australia.
| | - E L German
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - A Howard
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - H M Nabwera
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Alder Hey Children's Hospital, Liverpool, UK
- Centre of Excellence in Women and Child Health, Aga Khan University, Nairobi, Kenya
| | - A Matope
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - R Robinson
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - F Shiham
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - K Liatsikos
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - C McNamara
- Alder Hey Children's Hospital, Liverpool, UK
| | - S Kattera
- Alder Hey Children's Hospital, Liverpool, UK
| | - K Carter
- Alder Hey Children's Hospital, Liverpool, UK
| | - C M Parry
- Alder Hey Children's Hospital, Liverpool, UK
| | - J M Read
- Lancaster Medical School, Lancaster University, Lancaster, UK
| | - S J Allen
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Edward Francis Small Teaching Hospital, Banjul, The Gambia
| | - B C Urban
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, OX3 7LE, UK
| | - D B Hawcutt
- Alder Hey Children's Hospital, Liverpool, UK
- University of Liverpool, Liverpool, UK
| | - H Hill
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - A M Collins
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - D M Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, OX3 7LE, UK.
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Park J, Joo H, Maskery BA, Zviedrite N, Uzicanin A. Productivity costs associated with reactive school closures related to influenza or influenza-like illness in the United States from 2011 to 2019. PLoS One 2023; 18:e0286734. [PMID: 37279211 DOI: 10.1371/journal.pone.0286734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 05/19/2023] [Indexed: 06/08/2023] Open
Abstract
INTRODUCTION Schools close in reaction to seasonal influenza outbreaks and, on occasion, pandemic influenza. The unintended costs of reactive school closures associated with influenza or influenza-like illness (ILI) has not been studied previously. We estimated the costs of ILI-related reactive school closures in the United States over eight academic years. METHODS We used prospectively collected data on ILI-related reactive school closures from August 1, 2011 to June 30, 2019 to estimate the costs of the closures, which included productivity costs for parents, teachers, and non-teaching school staff. Productivity cost estimates were evaluated by multiplying the number of days for each closure by the state- and year-specific average hourly or daily wage rates for parents, teachers, and school staff. We subdivided total cost and cost per student estimates by school year, state, and urbanicity of school location. RESULTS The estimated productivity cost of the closures was $476 million in total during the eight years, with most (90%) of the costs occurring between 2016-2017 and 2018-2019, and in Tennessee (55%) and Kentucky (21%). Among all U.S. public schools, the annual cost per student was much higher in Tennessee ($33) and Kentucky ($19) than any other state ($2.4 in the third highest state) or the national average ($1.2). The cost per student was higher in rural areas ($2.9) or towns ($2.5) than cities ($0.6) or suburbs ($0.5). Locations with higher costs tended to have both more closures and closures with longer durations. CONCLUSIONS In recent years, we found significant heterogeneity in year-to-year costs of ILI-associated reactive school closures. These costs have been greatest in Tennessee and Kentucky and been elevated in rural or town areas relative to cities or suburbs. Our findings might provide evidence to support efforts to reduce the burden of seasonal influenza in these disproportionately impacted states or communities.
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Affiliation(s)
- Joohyun Park
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Heesoo Joo
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Brian A Maskery
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Nicole Zviedrite
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Amra Uzicanin
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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Indirect Protection from Vaccinating Children against Influenza A Virus Infection in Households. Viruses 2022; 14:v14102097. [PMID: 36298653 PMCID: PMC9610389 DOI: 10.3390/v14102097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 09/18/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022] Open
Abstract
Influenza vaccination is an important intervention to prevent influenza virus infection. Our previous analysis suggested that indirect protection is limited in an influenza B epidemic in Hong Kong. We further analyzed six influenza A epidemics to determine such potential. We applied a statistical model to estimate household transmission dynamics in the 3 influenza A(H3N2) and 3 pandemic influenza A(H1N1) epidemics. Then, we estimated the reduction in infection risk among unvaccinated household members when all children in households are vaccinated, with different assumptions on vaccine efficacy (VE). In the optimal scenario that VE was 70%, the reduction to the total probability of infection was only marginal, with relative probabilities ranged from 0.91–0.94 when all children in households were vaccinated because community was by far the main source of infection during the six epidemics in our study. The proportion of cases attributed to household transmission was 10% (95% CrI: 7%, 13%). Individual influenza vaccination is important even when other household members are vaccinated, given the degree of indirect protection is small.
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