Variolation

Variolation is the deliberate inoculation of a healthy person with matter taken from a smallpox sore or scab, producing a milder, controlled infection that confers immunity. China has the earliest well-documented practice, using nasal insufflation of powdered scabs; the sinologist Joseph Needham dated the first Chinese variolation to between 1567 and 1572. The Ottoman Empire also practiced variolation widely; Lady Mary Wortley Montagu, wife of the British ambassador in Constantinople, witnessed it there, had her own children inoculated in 1718 and 1721, and promoted the practice in England after 1721, helping establish it in Britain. Variolation killed an estimated 1 to 2 percent of recipients, against roughly 30 percent mortality from naturally acquired smallpox, but it could still transmit the disease to others. Edward Jenner's 1796 cowpox-based vaccine was safer than variolation and eventually replaced it entirely; the Royal College of Physicians had sanctioned variolation in 1754, four decades before Jenner's alternative made it obsolete.