Smallpox

What Is Smallpox? A deadly viral infection that once killed millions of people every year.

Symptoms: Fever, flu-like symptoms and distinctive skin lesions.

Can It Be Eradicated? Yes, a massive global vaccination program put an end to the disease in 1977.

Status: ERADICATED

Lessons from the Past

In 1959—when the eradication campaign began—smallpox ranged across 60 countries, putting about 60% of the world’s population at high risk for infection. Today, the virus only exists in two secure laboratory facilities in the U.S. and Russia.
© AMNH

One of history’s deadliest diseases, smallpox is estimated to have killed more than 300 million people since 1900 alone. But a massive global vaccination campaign put an end to the disease in 1977—making it the first disease ever eradicated.

Eradicating smallpox prevented millions of deaths and—by removing the need to treat and prevent the disease—saves many countries billions of dollars. Perhaps just as important: it showed the world that disease eradication was possible. Today, we are still applying the lessons learned from the successful smallpox eradication effort.

A Virulent Virus

Tuareg Girl. Mali, 1967 | Injector guns, like the one in this photograph, were used to deliver vaccine in the early years of the smallpox eradication campaign. But by the late 1960s, health workers had switched to a simpler “bifurcated needle,” which was easier, safer and cheaper.
Centers for Disease Control and Prevention

The virus that causes smallpox comes in two forms—the relatively mild Variola minor and its deadlier cousin, Variola major. Over the course of millennia, these tiny infectious particles traveled the globe along trade and exploration routes, afflicting victims with high fevers and numerous raised lesions on their skin. Death followed in one-third of Variola major cases. Even when victims survived, smallpox often left the survivors scarred for life. Although the first smallpox vaccine appeared in 1796, outbreaks continued well into the 1900s. Large-scale vaccination finally eliminated smallpox from the United States in 1949, but the disease spread freely in other parts of the world for three more decades.

Smallpox Patient. Early 1900s | Smallpox infection is typically identified by the raised lesions that form on a patient’s face and body.
© AMNH

The End of Smallpox

In 1959, the World Health Organization announced an audacious goal—the eradication of smallpox. Although no human disease had ever been eradicated, smallpox was a good candidate: it was easily diagnosed, had an effective vaccine and did not live in any other animal host. The effort began slowly, but after a second resolution in 1966, international cooperation grew and the campaign accelerated. Technological innovations such as freeze-dried vaccine and the bifurcated needle made vaccination more effective and simpler to administer. Initially, health workers conducted mass vaccinations, but over time they switched to a more targeted strategy. Teams would quickly track down new cases, isolate the infected, and vaccinate all of those who may have had contact with the infected person.

Smallpox Vaccination. East Pakistan (now Bangladesh), 1965 | Floods, famine and civil war nearly foiled eradication efforts in the country now known as Bangladesh. Infrastructure and security concerns are often still the biggest obstacles to disease eradication.
World Health Organization/Jean Mohr