The world’s biggest COVID-19 vaccine study got underway Monday with the first of 30,000 planned volunteers helping to test shots created by the US government — one of several candidates in the final stretch of the global vaccine race.
There’s still no guarantee that the experimental vaccine, developed by the National Institutes of Health and Moderna Inc., will really protect.
The needed proof: Volunteers won’t know if they’re getting the real shot or a dummy version. After two doses, scientists will closely track which group experiences more infections as they go about their daily routines, especially in areas where the virus still is spreading unchecked.
Several other vaccines made by China and by Britain’s Oxford University earlier this month began smaller final-stage tests in Brazil and other hard-hit countries.