How well it works
Large studies in the U.S., Mexico and Britain found two doses of the Novavax vaccine were safe and about 90% effective at preventing symptomatic COVID-19. When the delta variant emerged last summer, Novavax reported a booster dose revved up virus-fighting antibodies that could tackle that mutant.
Typical vaccine reactions were mild, including arm pain and fatigue, but regulators did warn about the possibility of a rare…