Both vaccines require two doses, spaced several weeks apart. Then researchers will have to wait to see whether people get infected or sick with COVID-19.
TUESDAY, July 28, 2020 (HealthDay News) -- As the U.S. coronavirus case count passed 4.3 million on Monday, companies launched the final phase of testing for two potential COVID-19 vaccines.
In one trial begun on Monday, the first of 30,000 volunteers were either given a vaccine developed by Moderna Inc. and the U.S. National Institutes of Health or a placebo shot, the Washington Post reported.
Pharmaceutical giant Pfizer also announced Monday that it was starting a 30,000-person final phase vaccine trial, to be conducted at 120 sites globally.