University of Pittsburgh had begun immunization experiments in monkeys using dead polio virus. Soon, however, Salk began to test inoculations in paralyzed polio patients and by 1953 human trials among the general population were initiated. By the spring of the following year, the largest controlled field trials in medical history were underway, and by 1955 the vaccine developed by Salk and his researchers was declared effective. By 1962, Salk's vaccine had reduced the incidence of polio in the United States by 95 percent. The breakthroughs in immunology and vaccine development at Pitt by Salk and his team are considered one of the most
Salk Institute for Biological Studies draw the best researchers in the world. Salk and Kahn – having both descended from Russian Jewish parents that had immigrated to the United States – had a deeper connection than just mere partners on an architectural project. The results of their connection is seen in the design that resulted from their collaboration. The original buildings of the Salk Institute were designated as a historical landmark in 1991. The entire site was deemed eligible by the California Historical Resources Commission in 2006 for listing on the National Register of Historic Places. The institute has three Nobel laureates on its faculty: