What is smallpox?

Smallpox is caused by variola virus. It is an “old” disease, having naturally occurred throughout the world for many centuries. Mortality is estimated at 30%. Smallpox was the first disease for which a vaccine was demonstrated when persons were “vaccinated” using cowpox in 1796. Smallpox vaccine was routinely administered in the U.S. until 1972 when it was discontinued. The last naturally occurring case of smallpox in the world occurred in 1977, and the world was declared to be smallpox-free in 1980. No smallpox cases have appeared since that time.

What are the symptoms of smallpox?

  • Initial symptoms include high fever, fatigue, headache, and backache. Abdominal pain and delirium may also occur.
  • Two to three days following initial symptoms, a raised red rash appears in the mouth and throat, on the face and forearms, then spreads to the trunk and legs.
  • Within 1-2 days, the rash changes to round, raised blisters that fill with pus.
  • Early in the second week, the round pus-filled pox begin to crust and scabs develop.
  • After about 3-4 weeks, the scabs fall off, leaving pitted scars.



Smallpox Information for the Public Smallpox Information for Public Health Officials


Related Links

CDC - Smallpox Page