Smallpox Facts

Smallpox is an infectious disease caused by a virus similar to the one that causes chickenpox. Smallpox was eliminated from the world as a result of widespread vaccines. Because of successful vaccines, there have been no naturally occurring smallpox worldwide since the late 1970s. Before it was eliminated, it was a serious infectious disease that was highly contagious. Most people recovered, but 3 out of 10 people died from the disease. There are vaccines to protect people from smallpox. Smallpox vaccines are not currently advised for the general public because smallpox has been wiped out. If a public outbreak occurs, health officials would use smallpox vaccines to control it.

Smallpox is spread from person to person by saliva during close contact and by contact with the fluid from the skin rash. The virus also spreads when coughed or sneezed droplets from the nose or mouth spread to others. The contagious period begins when symptoms appear. This may be 2 to 3 days before the rash starts, however the most contagious stage is when the rash appears. The disease remains contagious until all scabs have dried and fallen off (about 3 to 4 weeks). The scabs and fluid contain the virus. They can spread the disease through contaminated clothing or bedding.

Symptoms occur 1 to 2 weeks after exposure. Symptoms begin with high fever, fatigue, and headache for 2 to 4 days. A rash starts as small red spots on the tongue and in the mouth. These spots change into sores that break open and spread large amounts of virus into the mouth and throat. This rash then often spreads to all parts of the body within 24 hours. The spots become blisters and fill with pus. The blisters then break open and crust over.

Treatment for smallpox includes staying hydrated and taking care of the lesions so they do not become infected. Antiviral medicines have been approved for the treatment of smallpox and would be available only if a public outbreak occurs.