The first polio vaccine, developed by Jonas Salk, was trialled in 1954. It was a new hope against a disease that affected children, often resulting in paralysis. The inactivated-virus vaccine was safe, effective and administered through injection.
A few years later, Albert Sabin developed an attenuated live-virus vaccine that could be administered orally. An early example, dating to the 1960s, can be found in the RPS Museum. The oral vaccine was preferred because it was easy to administer and could even result in passive immunisation.
The World Health Organization uses both vaccines as part of its polio eradication initiative. Globally, polio cases have decreased by 99% since 1988.