Inoculation
Inoculation was not widely used in China until the 'Longqing Emperor'  in the 16th century. This was written by Yu Tianchi. Inoculation using the most deadly strain of the virus was banned from use in China to prevent high death rates. Inoculation is documented to have been used in India in the 18th century. It may have been used earlier than that, but there is no evidence to prove this.