Inoculation was introduced to America by a slave.

Few details are known about the birth of Onesimus, but it is assumed he was born in Africa in the late seventeenth century before eventually landing in Boston. One of a thousand people of African descent living in the Massachusetts colony, Onesimus was a gift to the Puritan church minister Cotton Mather from his congregation in 1706.

Onesimus told Mather about the centuries old tradition of inoculation practiced in Africa. By extracting the material from an infected person and scratching it into the skin of an uninfected person, you could deliberately introduce smallpox to the healthy individual making them immune. Considered extremely dangerous at the time, Cotton Mather convinced Dr. Zabdiel Boylston to experiment with the procedure when a smallpox epidemic hit Boston in 1721 and over 240 people were inoculated. Opposed politically, religiously and medically in the United States and abroad, public reaction to the experiment put Mather and Boylston’s lives in danger despite records indicating that only 2% of patients requesting inoculation died compared to the 15% of people not inoculated who contracted smallpox.

Onesimus’ traditional African practice was used to inoculate American soldiers during the Revolutionary War and introduced the concept of inoculation to the United States.