April 12th, 2025
This day in April marks the anniversary of announcement that the polio vaccine developed by American physician Dr. Jonas E. Salk was "safe", potent and effective". Incidence of infantile paralysis or poliomyelitis, declined by 95% following introduction of preventive vaccines. The first mass inoculations of children with the Salk vaccine had begun in Pittsburgh in 1954.
Source: www.historyofvaccines.org/content/articles/history-polio-poliomyelitis