Smallpox Eradication: How the World Defeated a Deadly Disease
In short: Smallpox killed an estimated 300 million people in the 20th century alone. A WHO-led global campaign using surveillance and ring vaccination eradicated it; WHO declared it eradicated in May 1980.
The intensified programme
WHO launched the Intensified Smallpox Eradication Programme in 1967, when the disease was still endemic in over 30 countries. Mass vaccination alone was not enough in dense, mobile populations.
Surveillance and containment
The winning strategy was 'surveillance and containment' — find every case fast, isolate it, and vaccinate contacts in a ring around it. Bifurcated needles and freeze-dried vaccine made field work easier.
The last cases
The last natural case of the severe form was in Bangladesh in 1975, and the last natural case overall was Ali Maow Maalin in Somalia in 1977. Nepal, which shared a long open border with India, reported its last cases in the mid-1970s. The World Health Assembly declared smallpox eradicated on 8 May 1980.
Key takeaways
- Smallpox is the only human disease ever eradicated.
- Ring vaccination and active case search were key.
- Polio and Guinea worm are the next eradication targets.
Common questions
Is smallpox vaccine still given?
No routine vaccination is given since eradication; stocks are kept for emergencies.
What lessons apply today?
Strong surveillance, community trust and targeted vaccination remain central to measles and polio programmes.
References
Educational content by PHC-Nepal. It does not replace advice from a qualified health professional.