1979 – Eradication of Smallpox:

The culmination of a decades-long global vaccination campaign, the World Health Organization (WHO) officially declared smallpox eradicated on December 9, 1979. This marked the first time in history that a human infectious disease had been eradicated through intentional efforts. The success of the smallpox eradication program showcased the immense power and effectiveness of vaccination on a global scale, setting a precedent for future efforts to eliminate other infectious diseases.