1947

Dean William McEllroy of Pitt’s School of Medicine recruited Jonas Salk from the University of Michigan to establish a virus research program.

1948

Isabel M. Morgan of Johns Hopkins University demonstrated that chemically inactivated poliovirus from monkey spinal cords induced immunity when injected into monkeys. This supported Salk’s belief from his work with inactivated influenza vaccines that a killed-virus vaccine might work.

1949

By the end of 1949, Salk had built laboratories in the basement of the Municipal Hospital (now Salk Hall) and assembled his core research team, including Youngner. Salk secured grants for his work from the National Foundation for Infantile Paralysis and the Sarah Mellon Scaife Foundation.

1951

The Pitt team used a new method created at Harvard University to grow poliovirus. Youngner developed new methods for growing the virus in culture. Using its own techniques, the team grew the virus in large quantities and continued to focus on a killed-virus vaccine.

1952

The Pitt team confirmed that there were only three strains of disease-producing poliovirus. The team began growing the virus at unprecedented levels. The team vaccinated monkeys using killed poliovirus. The monkeys had no adverse side effects and showed high levels of protective antibodies. After that success, Salk used the vaccine on children recovering from polio; the vaccine produced even higher levels of antibodies against the virus. The worst polio epidemic in U.S. history was the summer of 1952, with 57,628 cases. The March of Dimes’ effort to stop the disease became the largest private fundraising campaign ever.

1953

After Salk and the other Pitt researchers inoculated themselves and their family members, Salk began the first community-based pilot trial of the vaccine in the Pittsburgh suburb of Sewickley. Nearly 700 children and adults received the vaccine by year’s end. Youngner developed a method to more efficiently measure antibody levels.

1954

Upon reviewing the results of the Salk team’s pilot vaccination program involving thousands of Pittsburgh school children, the National Foundation for Infantile Paralysis recommended a large-scale national trial. On April 26, the largest field trial in the history of medicine was launched.

1955

On April 12, based on the national field trial, the killed poliovirus vaccine developed at the University of Pittsburgh was deemed “safe, effective, and potent.”