Isolation Strategies to Contain an Outbreak

Ring Vaccination Strategy

The Ring Vaccination strategy has been used successfully in the past. This involves vaccinating not only contacts of the case, but also the contacts of contacts in order to interrupt the chain of transmission. This has been so useful because we know that most transmission occurs from close contact.

While ring vaccination strategy is our primary means of stopping the chain of transmission, we know that it depends on the prompt identification of contacts, which will mean having trained staff who can do this. This strategy allows us to conserve a limited vaccine supply and it minimizes the risks of adverse events by covering only those who are at highest risk.

Contacts are defined as those having face-to-face contact with a smallpox case, usually within 6 and a half feet, and/or those who are household members of a smallpox case. If we can immunize them within 4 days of exposure, we might be able to prevent a case completely, or at least lessen the severity of the disease if they’re already infected. These contacts should be monitored for fever, the first indication of possible smallpox infection, for 18 days from their last exposure to the smallpox case. For contacts of a smallpox case, there are no contraindications for the use of vaccine. Because of the infectiousness of smallpox, we know their risk of vaccine adverse events is far outweighed by their risk of getting the disease. 

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