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Was smallpox the first and only human disease eradicated by 1980?

NoParrot Fact Check · September 14, 2026

Fact-checked by NoParrot's 4-model methodology · Last verified September 14, 2026

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42

NoParrot Score

Mixed signals

Claim breakdown

Verified
1
Uncertain
1
Disputed
1

Synthesis

Smallpox was declared eradicated by the World Health Organization in 1980, marking it as the first human disease to achieve global eradication. It is also considered the only human disease to have been eradicated worldwide.

The last known natural case of smallpox occurred in 1977, although a lab-associated case was documented in the UK in 1978. Variola virus samples are still maintained in high-security laboratories in both the U.S. and Russia.

While rinderpest, a cattle disease, was eradicated in 2011, there is disagreement on its status as the second disease overall to be eradicated or the only other eradicated disease besides smallpox. Some sources indicate no other human infectious disease has reached the status of eradication.

What each model said

  • Claude ✓ 2 ✗ 1
    Yes. Smallpox was the first human disease to be eradicated, declared so by the World Health Organization on May 8, 1980. It remains the only human disease ever eradicated. (Rinderpest, a cattle disease, was later eradicated in 2011, making it the second disease overall but the only other one besides smallpox.)
  • Grok ✓ 2 ✗ 2
    Yes, smallpox was the first and only human disease eradicated by 1980. The World Health Organization certified its global eradication in 1980 following the last known natural case in 1977, achieved through widespread vaccination campaigns. No other human infectious disease has reached this status.
  • GPT ✓ 2 ⚠ 1 ✗ 1
    Yes. Smallpox was declared eradicated by the World Health Organization in 1980, making it the first human disease eradicated globally. It is also still the only human disease to have been eradicated worldwide. The last naturally occurring case was in Somalia in 1977; a lab-associated case occurred in the UK in 1978. Variola virus samples are still retained in high-security labs in the U.S. and Russia.
  • Gemini ✓ All verified
    Yes, smallpox was the first and only human disease eradicated by 1980. The World Health Assembly declared smallpox eradicated in May 1980.

Models Used

  • Claude
  • Grok
  • GPT
  • Gemini

Disclaimer: This page summarizes the output of 4 frontier large-language models at a single point in time. NoParrot Score reflects cross-model consensus, not absolute truth. Models can be wrong, and consensus can be wrong with them. Treat this page as a research aid, not a final verdict.

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