Dr. Jonas Salk, Polio Vaccine, Pittsburgh, PA, 1955October 14, 2020/0 Comments/by https://pioneerinstitute.org/wp-content/uploads/logo_440x96.png 0 0 Andrew Loin https://pioneerinstitute.org/wp-content/uploads/logo_440x96.png Andrew Loin2020-10-14 10:24:492020-10-14 10:35:12Dr. Jonas Salk, Polio Vaccine, Pittsburgh, PA, 1955