The result have not yet been published or reviewed by independent scientists, but the government confirmed that Lilly's statement was accurate.

So, masks, disinfection and social distancing are needed. And people who work in such facilities have to be careful and get tested if they think they may be infected, experts said.

The numbers are included in a joint study still underway by the Canadian Paediatric Surveillance Program that may ease parent fears about the risks of sending kids back to school, says principal investigator Dr. Fatima Kakkar.

Dr. Anthony Gordon of Imperial College London called the result “a huge step forward,” but added, “as impressive as these results are, it’s not a cure.”

Two other vaccine candidates began final testing this summer in tens of thousands of people in the U.S. One was created by the National Institutes of Health and manufactured by Moderna Inc., and the other developed by Pfizer Inc. and Germany’s BioNTech.

That directive was lifted in late May and hospitals gradually resumed performing those surgeries.