November 19, 2002

According to the Centers for Disease Control and Prevention, a smallpox vaccination, called vaccinia, is "generally safe," but there can be some adverse reactions. In a recent study, 36 percent of vaccinated adults were "sufficiently ill enough to miss work, school or other activities."

The vaccination

A successful vaccination will produce a skin lesion. The CDC recommends people cover it with gauze, as scratching can inadvertently move the virus in the fluid to other parts of the body and cause lesions there.

Possible side effects

In the area of injection:

• Some swelling and tenderness of nearby lymph nodes beginning three to 10 days after shot

   

• Other lesions could appear around the primary skin lesion

   

• Some possible inflammation

   

• 17 percent of adults in the recent study reported a fever of higher than 100 degrees within two weeks

   

• Possible rashes

   

• The CDC warns death is possible, though rare -- occurring in the past in about one to two cases per million vaccinations. This most commonly occurs in people with already weak immune systems. The vaccination also can cause swelling of the brain -- encephalitis.