Lecture Notes: History and Eradication of Smallpox

Introduction to Smallpox

• Smallpox: A historically significant disease, targeted by the first vaccine.
• Final major U.S. outbreak in 1947, New York City.
• Caused by the variola virus, characterized by blister-like lesions.
• Origin: At least 3000 years old, possibly from northeast Africa.
• Spread worldwide through trade, war, and colonization.

Impact and Mortality

• Easy transmission via airborne fluids.
• 30% mortality rate.
• Survivors often left with significant health issues (blindness, sterility, disfigurement).
• In the 20th century, smallpox killed approximately 300 million people worldwide.

Early Prevention and Vaccination

• Variolation: Early form of immunization using material from smallpox survivors.
  • Effective but risky (1-2% mortality rate).
• Breakthrough in 1796 by Edward Jenner:
  • Developed the first vaccine using cowpox.
  • Termed vaccination from "vacca," Latin for cow.

Smallpox and Vaccination in the 20th Century

• By 1947, the disease was less common in Europe and Americas but still prevalent elsewhere.
• New York City Outbreak (1947):
  • Triggered by travelers returning from Mexico.
  • Misdiagnosis led to delayed containment.
  • Massive vaccination campaign: 2.5 million vaccinated in NYC.

Control and Eradication Efforts

• Ring vaccination technique used effectively in NYC.
• Smallpox eradicated from the U.S. by 1952.
• WHO global eradication campaign in the 1960s.
• Last natural case in 1977, Somalia.
• Lab accident in 1978 was the last recorded death.

Post-Eradication Measures

• Virus stocks retained in the U.S. and Russia for research.
• Vaccines are still kept in reserve globally.
• Celebrated 40 years without smallpox deaths in 2018.

Conclusion

• Smallpox turned from a deadly epidemic to a historical footnote.
• Successful eradication showcases the power of vaccination campaigns.

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