In what year did Edward Jenner develop the smallpox vaccine, the world's first vaccine?
Answer1796
Jenner's smallpox vaccine launched the entire field of vaccination.
Source: Wikipedia (2025) en.wikipedia.org
Health · Facts & sources
Shot facts & stats
6 sourced facts about vaccinations and immunization shots, each with the context behind the number. 4 more are in today's round and appear here after it closes.
The basics
Going deeper
About how many deaths does the WHO estimate vaccines prevent worldwide each year?
Answerabout 3.5-5 million deaths a year
This annual estimate covers a wide range of vaccine-preventable diseases.
Source: World Health Organization, via Wikipedia (2025) en.wikipedia.org
In 2023, about how many children worldwide had not received a single vaccine dose ('zero-dose' children)?
Answerabout 14.5 million
These 'zero-dose' children remain a major focus of global immunization efforts.
Source: Wikipedia (2023) en.wikipedia.org
In the 1980s, about what share of children in developing countries were vaccinated against six major diseases?
Answerabout 20-40%
Global vaccination coverage has climbed enormously compared to that starting point.
Source: Wikipedia (2025) en.wikipedia.org
Expert level
A 2024 study estimated vaccines prevented about how many deaths worldwide over the past 50 years?
Answerabout 154 million deaths
The study, funded by the WHO, covered 50 years of global vaccination efforts since 1974.
Source: WHO-funded study in The Lancet, via Wikipedia (2024) en.wikipedia.org
Of those deaths prevented by vaccines since 1974, about how many were children under age 5?
Answerabout 146 million
Childhood immunization accounts for the large majority of lives saved by vaccination programs.
Source: WHO-funded study in The Lancet, via Wikipedia (2024) en.wikipedia.org
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