14th May 1796: Edward Jenner tests vaccination against smallpox using cowpox infection

Rather than committing an act of gross medical negligence Jenner was scientifically testing, and proving, that infection with the mild disease of cowpox gave immunity to the more dangerous smallpox disease.

By modern estimates smallpox was killing up to 400,000 people a year across Europe by the end of the 18th Century. It is also known to have devastated the leaders of the royal families of Austria, Spain, Russia, Sweden and France. Attempts to reduce the impact of the disease were already well established.

The process of smallpox inoculation, also known as variolation, involved purposely infecting a person with the smallpox disease using fluid from pustules on an already-affected patient. Although this was less risky than contracting the disease naturally, it was still a dangerous process. Therefore the ability to prevent smallpox using a safer alternative was highly desirable.

Jenner’s process was a medical revolution, although contrary to popular belief he was not the first person to link cowpox infection to smallpox immunity. For example Dr John Fewster had presented a paper called ‘Cowpox and its ability to prevent smallpox’ to the Medical Society of London in 1765, 31 years before Jenner’s experiment. However, Fewster never published his paper, and did not carry out any experiments to prove the connection.

Jenner conducted, recorded, and published a methodical scientific process it is he that is credited with the discovery of vaccination.