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.

Lab tests suggest certain antiviral drugs may be effective against the virus that causes smallpox. These drugs have not been tested in people who are sick with smallpox, however, so it's not known if these drugs are effective treatment options.

If you were vaccinated as a child

Immunity or partial immunity after a smallpox vaccine may last up to 10 years, and 20 years with revaccination. 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.