Seems the polio vaccine underwent more testing for longer period.
[These studies] were necessary to solve many problems before an oral polio vaccine could become a reality.” At first the vaccine virus was grown in cells taken from minced monkey kidneys. The vaccines were then safety-tested on rhesus monkeys, young mice, guinea pigs and rabbits, before being used on people #1
The 1954 field trials that followed, the largest in U.S. history at the time, were led by Salk’s former University of Michigan colleague, Dr. Thomas Francis, Jr. In the late 1950s, Polish-born physician and virologist Albert Sabin ...
Take-away points:
The 1954 polio vaccine field trials used a singular statistical design
Over 600 000 schoolchildren were injected with vaccine or placebo and over a million others participated as “observed” controls
This dual protocol illustrates both the power and the limitations of randomised clinical trials to legitimate therapeutic claims #2
On this day (April 26) in history – 1954 – Polio vaccine trials begin
On this day in 1954, the Salk polio vaccine field trials, involving 1.8 million children, begin at the Franklin Sherman Elementary School in McLean, Virginia. Children in the United States, Canada and Finland participated in the trials, which used for the first time the now-standard double-blind method, whereby neither the patient nor attending doctor knew
On April 12, 1955, researchers announced the vaccine was safe and effective and it quickly became a standard part of childhood immunizations in America. In the ensuing decades, polio vaccines would all but wipe out the highly contagious disease in the Western Hemisphere. #3
#2 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1114166/