I know the blankets were given, but they did not know they carried smallpox even though they were from fort’s hospital, but no one knew it would spread smallpox as no one knew of the virus.
The blankets were given in 1763. Jenner’s vaccine was not till 1796.
As I said, Bad air, Witchcraft and the Evil Eye were believed to be the real cause of such sicknesses.
Within a few years bacteria were beginning to be understood but virus were unknown, but guessed at, until the Electron microscope.
George Washington had small pox in 1751 while in Barbados with his brother Lawrence. It was well known by 1763.