Ring vaccination is a disease-control strategy that 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 identified and vaccinated. Then a second "ring" of people who may
have been exposed to the first ring were also identified and vaccinated.
Many disease-control experts support ring vaccination as an
alternative to mass vaccination of the American public.
How this information was developed to help you make better health decisions.