Yes! A little more about Onesimus, the man who described the process to Rev Mather, who had been given as a slave to Rev Mather as a gift from the Rev’s congregation. This inoculation process was well known for centuries throughout sub Saharan Africa, India, Turkey, and it was the stubbornness of the white folks who refused to believe it.

A really fascinating story!

https://en.wikipedia.org/wiki/Onesimus_(Bostonian)?wprov=sfti1