In the early 19th century, British people finally had access to the first vaccine in history, one that promised to protect them from smallpox, among the deadliest diseases of the era. Many Britons were skeptical of the vaccine, however, with fears extending well beyond the fatigue and sore arm that go along with many modern shots. The side effects they dreaded were far more terrifying: blindness, deafness, ulcers, a gruesome skin condition called “cowpox mange” — even sprouting hoofs and horns.
With that, the world’s first anti-vaccination movement was born.
Source: First anti-vaccine movement arose from smallpox mandate in England | The Washington Post