Prevention

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 a smallpox vaccine, which can prevent or lessen the severity of the disease if given within four days of exposure to the smallpox virus.

Two vaccines are available. One vaccine (ACAM2000) 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 it's not recommended that everyone be vaccinated at this time. The potential risks of the vaccine outweigh the benefits, in the absence of an actual smallpox outbreak.

A second vaccine, a modified vaccinia Ankara vaccine (Jynneos), has been found to be safe, and it can be used in people who aren't able to take ACAM2000, who have weakened immune systems or who have skin disorders.

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.