FDA Says Novavax Covid-19 Shot Effective but Signals Safety Worry

Novavax Inc.’s vaccine was 90% effective at preventing Covid-19 in its pivotal trial, but the performance came before the emergence of the Omicron variant that has eluded vaccines more than earlier strains, US health regulators said.

The Food and Drug Administration also expressed concern Friday that six people who had taken Novavax’s vaccine during various studies developed heart-inflammation conditions known as myocarditis and pericarditis.