A POLIO DISASTER HELPED SHAPE VACCINE SAFETY. HERE’S WHY THAT MATTERS FOR THE CORONAVIRUS

Dr. Peter Salk still remembers the day his father learned the American manufacturers of the revolutionary polio vaccine he developed had messed up a batch -- with deadly consequences. © Provided by Global News Young girls are shown in the Polio girls' ward at Sick Kids Hospital in a 1937 handout photo in Toronto. The mystery illness that paralyzed and killed mostly children across Canada ...