Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Effect of changing start date for facemask adoption, shown by the blue dashed line. (a–d) T + 30d, T + 60d, T + 90d, T + 120d, respectively. The first lock-down period started at T + 90d. Earlier adoption of facemasks (a) has a different y-axis scale, because the end values of total removed are significantly lower. Even when implemented at T+120 days, 100% adoption of facemasks by the public stops the occurrence of additional COVID-19 pandemic waves.
