In 1800, the first successful vaccination performed in the U.S. using cowpox serum to prevent smallpox was given by Harvard’s Dr. Benjamin Waterhouse upon his five year-old son, Daniel, in Massachusetts. Waterhouse was one of the best educated American physicians of his time. Following the latest claims by Edward Jenner, he imported cowpox vaccine for his son and a servant boy. Waterhouse continued vaccinating with success, but in the rush to follow him, others administered impure vaccine and some people died; there was a backlash. Stressing the necessity of pure vaccine, he continued to promote vaccination and was instrumental in its success in America. more