Smallpox: Symptoms, Spread, and Treatment

What Is Smallpox?

Smallpox is a serious infectious disease caused by a virus that’s no longer found in nature. It was passed from person to person. People with smallpox had flu-like symptoms and a rash that would spread across their bodies.

Smallpox was deadly. About 30% of people who got smallpox died. In the 1900s, before smallpox was eradicated in 1980, it killed about 300-500 million people around the world. The World Health Organization (WHO) called smallpox “one of the most devastating diseases known to humanity.”

Smallpox history

Historians believe that smallpox has been around for at least 3,000 years. This is based on smallpox-like rashes found on Egyptian mummies from the 18th and 20th Egyptian dynasties. Historians say that the growth of civilization and exploration, as well as expanding trade routes, caused the disease to spread to other countries and continents.

People began to notice that those who got smallpox and survived never got it again. They realized that the best way to prevent getting sick was to expose yourself to the virus. This was often done by inhaling or rubbing the material from a smallpox sore onto the skin. Eventually, English doctor Edward Jenner learned that exposing people to the similar but less deadly cowpox virus helped protect them from smallpox.

Sometime in the 1800s, the smallpox vaccine was modified to use a poxvirus that was similar to smallpox but less harmful. However, the disease continued to infect people around the world. The last smallpox outbreak in the U.S. happened in 1949.

In 1967, WHO launched a plan to wipe out smallpox around the world through widespread immunization and surveillance. As a result, no cases of smallpox have happened since 1977. WHO declared it eradicated in 1980.

Today, scientists keep only a small amount of the virus alive under tightly controlled conditions in the U.S. and Russia for medical research.

Routine smallpox vaccinations stopped in the U.S. and in many other countries in 1972, and in all other WHO member countries by 1986. Many adults living today likely got the vaccine as children.