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HIV/AIDS pandemic
identified 1981; about 42 million deaths since (UNAIDS estimate)· Event· Global
Well documentedSolid records, physical evidence or scientific consensus.
A still-ongoing pandemic of HIV, a virus that destroys the immune system, first recognized in 1981.
See it on the History map →What happened
US doctors reported rare pneumonias in young gay men in June 1981. The virus, HIV, was identified in 1983–84. It spreads through blood, sex and from mother to child. Untreated, it leads to AIDS, in which ordinary infections become deadly. Sub-Saharan Africa has been hit hardest. Combination antiretroviral drugs, from 1996, turned it into a manageable chronic illness, and programs such as the US PEPFAR (2003) brought them to millions in poor countries.
Why it matters
It has killed about 42 million people, by UNAIDS estimates, and transformed activism, public health and how drugs are tested, priced and distributed worldwide.
How we know
UNAIDS and WHO data, medical case reports, and genetic studies tracing HIV to a chimpanzee virus that crossed to humans in central Africa in the early 1900s and spread from Kinshasa from about 1920.
Still debated
There is still no vaccine or general cure; only a handful of people have been cured, through risky bone-marrow transplants.
Connections (2)
▸Vaccines and germ theory laid the science for drugs that control HIV/AIDS pandemicMostly agreed
The connection
Germ theory taught scientists to hunt for the specific agent behind a disease. After AIDS was recognized in 1981, researchers identified the virus, HIV, by 1983 to 1984 and had blood tests by 1985. Drugs targeting the virus's enzymes, combined into triple therapy from 1996, turned a near-certain death sentence into a manageable chronic condition.
When and how
Pasteur Institute, Paris (Luc Montagnier and Françoise Barré-Sinoussi, 1983) and the US National Cancer Institute (Robert Gallo, 1984); combination therapy announced in Vancouver in 1996.
How sure are we?
The published discoveries, the 2008 Nobel Prize for identifying HIV, and UNAIDS data showing AIDS deaths fell by about 70% from their 2004 peak.
Debates and open questions
Despite decades of effort, no HIV vaccine works yet, because the virus mutates fast and hides inside cells; a cure remains an open goal.
▸HIV/AIDS pandemic has killed about as many as the 1918 flu pandemicMostly agreed
The connection
The 1918 flu killed tens of millions in about two years; HIV has killed about 42 million over four decades. The 1918 toll is so uncertain, roughly 17 to 50 million or more, that the two are broadly comparable. The difference is speed: HIV kills slowly over years, while the flu struck within days.
When and how
Worldwide, 1918–1920; HIV deaths counted by UNAIDS from 1981 to today.
How sure are we?
UNAIDS publishes yearly HIV death estimates; 1918 figures come from historical records and demographic modeling, with very wide ranges.
Debates and open questions
Which killed more depends on which 1918 estimate you use; older figures of up to 100 million are now considered too high by many researchers.