Speaker
Description
Many non-pharmaceutical interventions (NPIs) were implemented to target contact patterns that drove wild-type SARS-CoV-2 transmission in Canada; however, it is challenging to determine and understand their individual and joint effectiveness in different age groups. We developed an age-structured Susceptible-Exposed-Infectious-Recovered (SEIR) deterministic model and stratified the population into two age groups: children/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 NPI timelines were compiled for three urban Canadian regions (Calgary, Greater Vancouver, and the Greater Toronto Area) between Mar 2020-Feb 2021. 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. 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. The model and results can inform targeted NPI implementation and aid in resource planning and preparedness for future emerging disease outbreaks.
