TIMELINES: The vaccine for what disease was declared 80 – 90 percent effective on April 12, 1955?

April 12, 2012 Updated: September 29, 2015

Thursday, April 12, 2012


April 12, 1955, at the University of Michigan in Ann Arbor, Dr. Thomas Francis Jr. announced an 80 to 90 percent rate of effectiveness for the Salk polio vaccine in preventing paralytic polio. The vaccine was developed by Jonas Salk, a former student at the university. The announcement was made following two years of national field trials involving an unprecedented 1,800,000 children. In making the announcement, Francis concluded that the vaccine is “Safe, effective, and potent.”


This week, a group of Indian medical experts in pediatrics released a report criticizing the overall effectiveness of India’s polio eradication campaign. On Feb. 25, India was officially struck off the list of polio-endemic countries by the World Health Organization, after going one year without reporting any cases. In the critical report, doctors Vashisht and Puliyel questioned the campaign’s failure to thoroughly investigate the rise in the incidence of non-polio acute flaccid paralysis (NPAFP) in areas where many doses of vaccine were administered. In a statement, the doctors said, “From India’s perspective the exercise has been extremely costly both in terms of human suffering and in monetary terms. It is tempting to speculate what could have been achieved if the $2.5 billion spent on attempting to eradicate polio, were spent on water and sanitation and routine immunization.”