What role did the World Health Organization play in eradicating smallpox?

In 1967, the World Health Organization (WHO) launched an intensified global campaign to eradicate smallpox, a feat of international cooperation that transcended political divides during the Cold War.12

While the initial strategy focused on mass vaccination, the program’s success was driven by a shift to "ring vaccination." This method involved health workers tracking outbreaks, isolating infected individuals, and vaccinating everyone in the surrounding area to interrupt transmission. Because the virus had no animal reservoir and symptoms were easily identifiable, this targeted approach effectively contained the disease.2

Following the last recorded endemic case in Somalia in 1977, the WHO conducted careful monitoring to ensure the virus had disappeared. In 1980, the organization officially declared smallpox eradicated, marking it as the only human infectious disease to be eliminated through such efforts. This achievement remains a landmark in public health, demonstrating the power of global collaboration to overcome persistent threats.123