A retrospective modelling analysis of the effect of control measures on the transmission of SARS-CoV-2 in Canada
We consider the COVID-19 pandemic between March 2020 to February 2021 in selected Canadian regions. This period was dominated by the wild-type strain of SARS-CoV-2 and occurred prior to widespread vaccination roll-out. We incorporate age-specific control measures in a Susceptible-Exposed-Infectious-Recovered (SEIR) deterministic model with two age groups: youth aged 0-19 years, and adults aged 20+ years. We fit this model to COVID-19 case data over sequential time frames that capture the various changes in public health control measures during this period in each region. The age-specific control parameters of the fitted model are then adjusted to simulate alternative policy scenarios and assess their relative potential effectiveness in reducing the Fall/Winter epidemic peaks. In this period, we find that a moderate increase in adult-specific control measures has a larger effect on reducing case counts when compared with a drastic strengthening of control measures in youth.