Health & biology · 1721

Variolation

Deliberately infecting people with mild smallpox cut death rates from about 30 to 2 percent.

Long practised in China, India and the Ottoman Empire, variolation was brought to England in 1721 by Lady Mary Wortley Montagu. It proved immunity could be induced, setting the stage for vaccination.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

Hippocratic medicine 400 BCE

What it led to 1

Vaccination 1796

Related measurements

The dashed line marks when it first worked.

Smallpox deaths in London, 1629-1902 Latest: 1.59 % of all deaths (1902) Source: Our World in Data

Life expectancy in the UK since 1543 Latest: 81.3 years (2023) Source: Our World in Data