In the event of an outbreak, people who had smallpox would be kept in isolation in an effort to control the spread of the virus. Anyone who had contact with someone who developed an infection would need the smallpox vaccine, which can prevent or lessen the severity of the disease if given within four days of exposure to the smallpox virus.

The vaccine uses a live virus that's related to smallpox, and it can occasionally cause serious complications, such as infections affecting the heart or brain. That's why a general vaccination program for everyone isn't recommended at this time. The potential risks of the vaccine outweigh the benefits, in the absence of an actual smallpox outbreak.

If you were vaccinated as a child

It's not known how long immunity lasts after a smallpox vaccine. It's likely that a previous vaccination would offer partial immunity, which might protect against the disease's most-serious complications. But if an outbreak ever occurred, people who were vaccinated as children would still likely receive a new vaccination after direct exposure to someone with the virus.

Aug. 16, 2014

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