Fig. 3

Dynamics of SARS-CoV-2 epidemic in Rhode Island under three different transmission scenarios from 1 December 2020 onwards. The vaccine profile shown here has efficacy half-life of 180 days and slope of 2. The vaccination campaign covers 300,000 people (28.3% population coverage) and ends on 4 March 2021. Under medium transmission (middle column), the population mixing parameter is assumed to remain at the mean mixing level from September through November 2020. This mixing parameter (top row) is reduced by 30% and increased by 30% to achieve low and high transmission settings, respectively. The second and third row show the size of susceptible (S) and symptomatic (I) compartment over time. The fourth row shows the cumulative deaths, both at home and in hospitals. The last row shows seroprevalence (including vaccinees) in Rhode Island from 15 August 2020 to 30 June 2021. With no vaccination (dotted gray line), attack rate would reach 34.9%,45.9%, and 58.2% by 30 June 2021 under low, medium, and high transmission settings, respectively. Scenarios and dynamics for Massachusetts shown in Additional file 1: Figure S14