Who developed the polio vaccine using a double-blind randomized experiment?

• A. Jonas Salk
• B. Albert Sabin
• C. Louis Pasteur
• D. Edward Jenner

Answer: (A)

Testing a vaccine's effectiveness relies on controlled, unbiased comparisons between those who receive the vaccine and those who do not. Jonas Salk led the large 1950s trial of the inactivated polio vaccine, designed as a random assignment to vaccine or placebo and carried out in a double-blind manner so that neither participants nor evaluators knew who received which treatment. This setup minimizes bias and placebo effects, making it possible to attribute differences in polio incidence to the vaccine itself. The trial's strong design and large scale provided clear evidence of safety and efficacy, paving the way for widespread use. Albert Sabin developed the oral polio vaccine, but his work followed later and involved different testing approaches. Louis Pasteur and Edward Jenner contributed foundational vaccines for other diseases, not the polio vaccine tested in this double-blind trial.