On Mar. 22, 1954, Dr. Jonas Salkﾒs team began giving inoculations of a commercially prepared vaccine to some 2,500 children from seven parochial schools in Pennsylvania. These schools were St. Lawrence, St. Stephens, Holy Rosary, Sacred Heart, Resurrection, St. Basil and St. George.

All inoculations given before this date were with a vaccine prepared in Salkﾒs lab at the University of Pittsburgh.