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.
Introducing contact tracing with a different percentage of the population being smartphone users from day 27. (a) shows, with higher percentage of smartphone owners, less portion of the population are infected by the end of day 120. The shaded portion represents confidence interval. Variation of means of Rt is illustrated in (b)
