Jonas Salk

Oops! Jonas Salk worked to develop the polio vaccine. Try again.

Paul Offit

Oops! Paul Offit worked to develop a rotavirus vaccine. Try again.

Thomas Francis, Jr.

Correct! Thomas Francis successfully isolated the influenza virus at the University of Michigan in the early 1940s. He was a mentor to Jonas Salk, who would go on to develop the polio vaccine.