ABSTRACT
Interrupted time series analyses were conducted to measure the impact of social distancing policies (instituted on March 22, 2020) and of subsequent mandatory masking in the community (instituted on May 4, 2020) on the incidence and effective reproductive number of COVID-19 in São Paulo State, Brazil. Overall, the impact of social distancing both on incidence and Rt was greater than the incremental effect of mandatory masking. Those findings may reflect either a small impact of face masking or the loosening of social distancing after mandatory use of masks.
Coronavirus Infections, prevention & control; Facial Masks; Social Isolation; Local Strategies; Disease Transmission, Infectious
Thumbnail
Note. The two dashed vertical lines in the graphs represent, respectively, government decrees of social restriction (March 22) and universal use of masks in the community (May 4). Embedded in the graphics, regression coefficients for immediate impact and impact on time trends are presented. Beneficial impact of interventions with p-value < 0.05 are indicated in graphics: letter “a” for immediate impact and “b” for impact on long-term trend.