Created by Jonas Salk, the vaccine was hailed as the miracle drug that would conquer the dreaded illness that killed and paralyzed children. Eddy's job was to examine samples submitted by the companies planning to make it.

As she checked a sample from Cutter Laboratories in Berkeley, California, she noticed that the vaccine designed to protect against the disease had instead given polio to a test monkey. Rather than containing killed virus to create immunity, the sample from Cutter contained live, infectious virus.

Something was wrong. "There's going to be a disaster," she told a friend.

As scientists and politicians desperately search for medicines to slow the deadly coronavirus, and as President Donald Trump touts a malaria drug as a remedy, a look back to the 1955 polio vaccine tragedy shows how hazardous such a search can be, especially under intense public pressure.

Despite Eddy's warnings, an estimated 120,000 children that year were injected with the Cutter vaccine, according to Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia.