What was the first vaccination?

The first vaccination invented was by Edward Jenner , an English physician, in 1796.  In those days, people lived in fear of Smallpox, which had a high mortality rate, and survivors were left with disfiguring scars.  Dr. Jenner observed that dairy maids who milked cows and got the “Cowpox” virus did not get Smallpox.  Cowpox is a virus similar to Smallpox but is a much milder disease for humans.  Dr. Jenner found a dairy maid who had active Cowpox skin lesions, and used a needle to inoculate an 8-year-old boy in 1796 from these lesions.  The boy became ill with Cowpox but never got Smallpox.