Summary of Chapter 23-28:
The final phases of Smallpox Eradication and post-eradication challenges

These final chapters focus on the last steps of the global smallpox eradication effort, including importations of smallpox into non-endemic countries, certification of eradication, and post-eradication policies. Despite global vaccination efforts, smallpox importations continued until the late 1970s, often triggering localized outbreaks. Certification of eradication required rigorous proof of disease elimination in every country. Following the official declaration of eradication in 1980, WHO shifted its focus to post-eradication strategies, including vaccine stockpiling, laboratory safety measures, and surveillance of monkeypox.

Chapter 23: Smallpox in non-endemic countries

While smallpox was being eradicated from endemic countries, cases continued to be imported into industrialized nations, particularly from South Asia and Africa. Between 1959 and 1974, 37 outbreaks occurred in non-endemic regions, with 34 in Europe, 1 in Canada, and 2 in Japan. Some of the most notable outbreaks included:

  • The Yugoslav Epidemic (1972): Imported from Iraq, resulting in a mass vaccination campaign.
  • The Birmingham Laboratory Outbreak (1978): A case caused by a lab accident, leading to the last smallpox-related death.
  • Airport and Travel-Related Cases: Several outbreaks were linked to air travel, refugees, and border crossings.

Governments responded with quarantine measures, emergency vaccination campaigns, and stricter travel regulations. However, as the WHO-led eradication program advanced, these outbreaks became rarer.

Chapter 24: The certification of eradication: concepts strategy and tactics

Certification was a multi-step process requiring scientific verification that smallpox transmission had ended worldwide. The WHO established international commissions to assess countries based on:

  1. Disease Surveillance Systems – Ensuring no undetected cases remained.
  2. Pockmark Surveys – Using facial scarring studies to identify past cases in remote areas.
  3. Laboratory Testing – Confirming suspected cases were not smallpox.
  4. Public Reporting Systems – Encouraging citizens and healthcare workers to report possible infections.

Countries were formally declared free of smallpox in phases, with the final certification completed in 1979.

Chapter 25: Certification by international commissions: 1973-1977

Between 1973 and 1977, WHO focused on certifying the last endemic regions. Special commissions reviewed 29 countries in Africa and Asia, ensuring eradication through on-the-ground verification. The most challenging countries included:

  • India and Bangladesh: Where massive vaccination efforts and house-to-house searches played a crucial role.
  • Sudan and Yemen: Which suffered from civil wars and refugee crises, complicating efforts.
  • Iran, Iraq, and Saudi Arabia: Where pilgrimages (Hajj) created high-risk transmission zones.

By 1977, smallpox transmission had been stopped globally, but final certification required two years of intensive monitoring.

Chapter 26: Certification of 29 countries of Africa and Asia: 1978-1979

After endemic transmission ended, certification focused on 29 additional countries that had historical cases but were not major smallpox reservoirs. This phase included:

  • Southern Africa: Countries like South Africa, Botswana, and Mozambique required additional reviews due to weak health infrastructures.
  • Southwestern Asia: Iran, Iraq, and the Gulf States implemented surveillance and containment policies.
  • Southeastern Asia: WHO teams worked in Thailand, Laos, and Vietnam, where smallpox was historically present but not well-documented.

These reviews confirmed no remaining smallpox cases, and the program prepared for the final global certification.

Chapter 27: The last steps – The horn of Africa and China

The final certification efforts focused on two regions:

  1. The Horn of Africa (Ethiopia, Somalia, Djibouti, Kenya) – The last known smallpox case was reported in Somalia in 1977. Due to ongoing conflicts, nomadic populations, and refugee movements, special measures were needed, including cash rewards for reporting cases.
  2. China – Though smallpox was eliminated earlier, WHO had no direct access to Chinese eradication efforts until 1979. A team verified surveillance data, vaccine records, and laboratory containment policies before confirming eradication.

The final certification took place on October 26, 1979, exactly two years after the last recorded smallpox case. WHO formally declared smallpox eradicated on May 8, 1980.

Chapter 28: Post-eradication operations: implementation of the recommendations of the Global Commission

Once smallpox was eradicated, WHO implemented post-eradication policies to prevent future outbreaks. These included:

  1. Ending Routine Smallpox Vaccination – By 1984, all countries had discontinued mandatory smallpox vaccinations.
  2. Vaccine Stockpiling – WHO and some governments maintained emergency smallpox vaccine reserves in case of bioterrorism or accidental reintroduction.
  3. Containment of Variola Virus Stocks – Live smallpox virus was restricted to two labs:
    • Centers for Disease Control (CDC) in the USA.
    • Vector Institute in Russia.
    • All other stocks were destroyed to prevent unauthorized access.
  4. Surveillance of Monkeypox – As monkeypox cases increased in Zaire (now the Democratic Republic of Congo), WHO launched a monitoring program to ensure it would not become the next global threat.

Conclusion

The final phase of smallpox eradication required strict verification, documentation, and containment policies to prevent re-emergence. The success of the global smallpox eradication program remains a landmark achievement, proving that infectious diseases can be eliminated through coordinated international effort. WHO’s post-eradication policies ensured that the world remains prepared against future risks, including bioterrorism and emerging poxvirus threats.