Variolation, using a small dose of disease, was historically used to reduce mortality compared to full infection.

“you know this is what we did with smallpox in the time of the Revolutionary War this is very elation smallpox is called variola and they used to take a small dose and put on to the skin that's very elation and they still a lot of people died because smallpox was very bad but a lot less people died then would have died from that from the actual full infection of smallpox”