In the winter of 1979, the world celebrated the end of smallpox, a highly contagious and often fatal viral infection estimated to have caused between 300 and 500 million deaths during the 20th century.
The virus was eradicated through an aggressive worldwide vaccination campaign, which itself ended in 1980. After all, with no virus, there was no longer a need for a vaccine. Now, researchers at UCLA say the elimination of the smallpox vaccine has allowed a related virus to thrive.
In the current online edition of Proceedings of the National Academy of Science, Anne Rimoin, an assistant professor of epidemiology at the UCLA School of Public Health, and colleagues report that 30 years after the mass smallpox vaccination campaign ceased, rates of a related virus known as human monkeypox have increased dramatically in the rural Democratic Republic of Congo, with sporadic outbreaks in other African nations and even the United States.
Until 1980, Rimoin said, the smallpox vaccine provided cross-protective immunity against monkeypox, a “zoonotic orthopoxvirus,” meaning it can be passed from animals to humans. Symptoms of monkeypox in humans include severe eruptions on the skin, fever, headaches, swollen lymph nodes, possible blindness and even death. There is no treatment.
“All you can do is provide supportive care,” Rimoin said. “There are no antibiotics. If you survive, the illness eventually runs its course.”