Polio vaccine The results of the field trial were announced 12 April 1955 (the tenth anniversary of the death of President Franklin D. Roosevelt, whose paralytic illness was generally believed to have been caused by polio). The Salk vaccine had been 60–70% effective against PV1 (poliovirus type 1), over 90% effective against PV2 and PV3, and 94% effective against the development of bulbar polio. Soon after Salk's vaccine was licensed in 1955, children's vaccination campaigns were launched. In the U.S, following a mass immunization campaign promoted by the March of Dimes, the annual number of polio cases fell from 35,000 in 1953
Jonas Salk Donna Lindsay, a master's candidate at the New York College of Social Work. David Oshinsky writes that Donna's father, Elmer Lindsay, "a wealthy Manhattan dentist, viewed Salk as a social inferior, several cuts below Donna's former suitors." Eventually, her father agreed to the marriage on two conditions: first, Salk must wait until he could be listed as an official M.D. on the wedding invitations, and second, he must improve his "rather pedestrian status" by giving himself a middle name." They had three children: Peter, Darrell, and Jonathan Salk. In 1968, they divorced and, in 1970, Salk married French painter, Françoise