Ring vaccination is a strategy to control disease. It was used to
smallpox until the last naturally occurring case in
1977. When an infection was diagnosed, all people who were or may have been
exposed were found and vaccinated. Then a second "ring" of people who may
have been exposed to the first ring were also found and vaccinated.
Many disease-control experts support ring vaccination instead of mass vaccination of the American public.
How this information was developed to help you make better health decisions.