Not quite vaccines, variolation, which was the precursor to inoculation. But yes, it was known by Africans for many years that rubbing smallpox scars on a scratch in the skin of a child made them unlikely to die of smallpox later in life and that knowledge was told to Cotton Mather by his slave. It was highly resisted in America, however. Much more than anti-vaxxers resist today. But eventually, the knowledge gained from it led to inoculation, which came before vaccination. Washington ordered the Continental Army to be inoculated against smallpox.