Evidence map›Paper›PMID 41776444›Full record

ArticleBMC public health2026

Retrospective analysis of age-specific non-pharmaceutical interventions on wild-type SARS-CoV-2 in Canada.

Tanya Philippsen, P van den Driessche, Laura L E Cowen, Junling Ma

Abstract read
In one paragraph

Article in BMC public health, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

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4 · The record

Corrections and comments

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5 · Who and what money

Authors and funding

4 authors.

Tanya PhilippsenDepartment of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada.
P van den DriesscheDepartment of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada.
Laura L E CowenDepartment of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada.
Junling MaDepartment of Mathematics and Statistics, University of Victoria, Victoria, BC, V8W 2Y2, Canada. junlingm@uvic.ca.

Funding

Michael Smith Health Research BC COV2020-1061Natural Sciences and Engineering Research Council of Canada RGPIN-03789-2018Natural Sciences and Engineering Research Council of Canada RGPIN-2013-327025Natural Sciences and Engineering Research Council of Canada RGPIN-2016-03677Victoria Hospitals Foundation COV2020-1061
6 · The paper itself

Abstract

backgroundThe unmitigated spread of novel infectious pathogens, such as SARS-CoV-2, can result in significant disease burdens and widespread societal impacts. The magnitude, severity, and duration of these events are influenced by factors such as contact patterns and the application and effectiveness of public health control measures. Many non-pharmaceutical interventions (NPIs) were implemented to target these heterogeneous drivers and modifiers of wild-type SARS-CoV-2 transmission in Canada; however, determining and understanding their individual and joint effectiveness on different populations is challenging. In this retrospective study, we delineate the impacts of age-specific NPIs in three urban Canadian regions (Calgary, Greater Vancouver, and the Greater Toronto Area) prior to widespread vaccination availability (March 2020-February 2021) and identify relative age-specific NPI effectiveness on mitigating wild-type SARS-CoV-2 transmission.

methodsWe developed an age-structured Susceptible-Exposed-Infectious-Recovered (SEIR) deterministic model and stratified our population into two age groups: children and youth (0-19 years) and adults (20+ years). The model incorporated contact mixing rates, wild-type SARS-CoV-2 age-specific susceptibility, and NPI strength. Detailed timelines for each region were compiled, capturing the time-dependent implementation of age-specific and population wide NPIs. Using maximum likelihood estimation, we determined regional baseline transmission probabilities in the absence of widespread NPIs, then estimated the subsequent time-dependent and age-specific NPI strength on transmission reduction. Finally, we considered counterfactual NPI scenarios and compared simulated regional age-specific epidemic trajectories with reported SARS-CoV-2 case data.

resultsThe age-specific and sequential time-dependent NPI strength on wild-type SARS-CoV-2 transmission reduction was estimated for each region during March 2020-February 2021. We observed that adult-specific contacts play a large role in transmission, and moderately-strengthened adult-specific NPIs were more effective in reducing transmission across all regions compared to a drastic strengthening of NPIs in children and youth (i.e., closing schools). These results held when varying temporal applications of singular and joint counterfactual NPI scenarios; however, regional contexts and data uncertainties caused varied levels of effectiveness.

conclusionsBy considering population heterogeneity, our retrospective study provides insight into age-specific NPI effectiveness on wild-type SARS-CoV-2 transmission. These findings and associated model can inform decision-making related to targeted NPI implementation and aid in resource planning and preparedness for future emerging disease outbreaks.

Indexed as

Communicable Disease ControlCOVID-19AdolescentAdultAge FactorsCanadaChildChild, PreschoolFemaleHumansInfantInfant, NewbornMiddle AgedRetrospective StudiesSARS-CoV-2Young AdultAge-structureDisease control policyEpidemicsMathematical epidemiologyPublic healthSARS-CoV-2SEIR model

Identifiers

PMID41776444
PMCPMC13063586

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LicenceCC BY-NC-ND
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.