Barbara Johnston, left, and Paula Richards wait in line on Dec. 29, 2020, at the East County Regional Library in Lehigh Acres, Fla., where the Florida Department of Health in Lee County is offering a limited number COVID-19 vaccines to high-risk frontline health care workers and those 65 and older. Since even the first shot appears to provide some protection against COVID-19, some experts believe that the shortest route to containing the virus is to disseminate the initial injections as widely as possible now. (Octavio Jones/The New York Times)