(NPR) Why Tens Of Thousands Of People Are Key To Testing A COVID-19 Vaccine

Why Tens Of Thousands Of People Are Key To Testing A COVID-19 Vaccine

Researchers in Miami hold syringes containing either a placebo or the candidate COVID-19 vaccine from Moderna. Their work is part of a phase three clinical trial sponsored by the National Institutes of Health.



Taimy Alvarez/AP


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Taimy Alvarez/AP

Shots - Health News

Why Tens Of Thousands Of People Are Key To Testing A COVID-19 Vaccine

Volunteers getting the shot help determine if a candidate vaccine works. But what with social distancing and masks, scientists must discern if it's the shot or these other measures preventing illness.