Final answer:
Jonas Salk developed the killed virus part of the polio vaccine which was introduced in 1955. The success of Salk's vaccine greatly reduced the incidence of polio and led to the routine dispensation of other childhood vaccines.
Step-by-step explanation:
The individual who developed the killed virus part of the polio vaccine was Jonas Salk. The vaccine that Salk developed used a killed or inactivated form of the poliovirus. It was first introduced in 1955 and was administered via intramuscular injection. Using the killed virus tested on the HeLa cell line, Salk's polio vaccine went through a rigorous nationwide experiment, involving over a million schoolchildren, to test its effectiveness. The successful development and mass immunization campaigns of the 1950s had a significant impact on the incidence of polio, leading to a reduction by 96 percent of polio cases in the U.S. by 1961.
After Salk's inactivated polio vaccine, a different type of vaccine, using a live attenuated virus, was developed by Albert Sabin and introduced in 1962 as an oral vaccine. Both Salk and Sabin vaccines were effective against all three serotypes of poliovirus. The success of these vaccines paved the way for the routine administration of childhood vaccines against other infectious diseases.