When Was the First Mass Vaccination Campaign?

Edward Jenner demonstrated in 1796 that inoculation with cowpox material protected against smallpox, publishing his results in 1798. The concept spread rapidly: by 1801, Jenner estimated over 100,000 vaccinations in Britain alone. Spain organised the Balmis Expedition in 1803-1806, one of the most ambitious early vaccination campaigns — it carried the vaccine around the world, from the Americas to the Philippines and China, using a chain of orphan children who passed cowpox from arm to arm during the voyage. Bavaria made smallpox vaccination compulsory in 1807, the first country to do so. The ultimate triumph came in 1980 when the WHO declared smallpox eradicated — the only human disease eliminated through vaccination. The campaign, which began in 1967 with a target of reaching every person on Earth, is considered the greatest achievement in public health history.