1721
From Ganfyd
Variolation or inoculation was in use in the UK and in Boston there was a natural experiment which indicated a sizeable advantage to variolation, at least on a population basis. The death rate from the preventive treatment was still around 2%. Against the background of the high incidence of Variola Major with a mortality rate around 33% of the 60% incidence that looked good, except to a sizeable minority of Puritan clergy who deemed it interference with god's will or witchcraft. During the debate god threw a lighted grenade into Cotton Mather's living room.
