<unk>  is a strategy to inhibit the spread of a disease by<unk> g those who are most likely to be infected. This strategy vaccinates the contacts of confirmed patients, and people who are in close contact with those contacts. This way, everyone who has been, or could have been, exposed to a patient receives the vaccine, creating a 'ring' of protection that can limit the spread of a pathogen.<unk>  requires thorough and rapid surveillance and epidemiologic case investigation. The Intensified Smallpox Eradication Program used this strategy with great success in its efforts to eradicate smallpox in the latter half of the 20th century.
Ring vaccination
Typhus vaccine
Polio vaccine
Typhoid vaccine
Rubella vaccine
Tetanus vaccine
Rabies vaccine
Measles vaccine