What diseases have been 100% cured?

The Two Diseases We’ve Truly Defeated

Throughout history, humanity has battled countless diseases, but only two have been completely eradicated—wiped out with such finality that they no longer exist in the wild. The most celebrated triumph is smallpox, a devastating illness that plagued humans for millennia, leaving survivors scarred or blind—and killing upwards of 300 million people in the 20th century alone.

Thanks to a relentless global vaccination campaign led by the World Health Organization, the last known natural case of smallpox occurred in 1977. In 1980, the disease was officially declared eradicated—a monumental achievement in public health. Today, the virus exists only in highly secure laboratories, a relic of a threat we’ve conquered.

The second eradicated disease might surprise you: rinderpest, a deadly virus that affected cattle and other cloven-hoofed animals. For centuries, rinderpest devastated livestock across Europe, Africa, and Asia, triggering famines and economic collapse wherever it spread. Like smallpox, it was highly contagious and often fatal.

Through coordinated surveillance, vaccination, and international cooperation—led largely by the Food and Agriculture Organization and the World Organisation for Animal Health—rinderpest was declared eradicated in 2011. It stands as a rare but powerful example of what’s possible when science, policy, and global collaboration align.

These two victories remind us that eradication is possible—but exceedingly rare. Diseases like polio and measles have seen massive declines, but remain in circulation. The lessons from smallpox and rinderpest underscore a simple truth: persistence, trust in science, and global unity are the only paths to truly defeating a disease once and for all.