1954 field trials of polio vaccine in 48 US states

The transcript describes the efforts of Dr. Jonas Salk in developing a polio vaccine. In 1954, Salk announced a potential vaccine, leading to a large-scale test involving 440,000 children. The first to be inoculated were Salk's own sons. The field test was the largest in medical history, with volunteer nurses and doctors participating.

What was the primary focus of Jonas Salk's work?

In what year did Jonas Salk announce that he might have found the answer to the vaccine?

What was the nature of the vaccine that Salk developed?

How many grammar school children participated in the vaccine testing?

Who were the first three children inoculated with the vaccine?