This vaccine did previously have emergency approval by the FDA for use but can now be marketed in the U.S. for use, the letter said.

After a six-week delay, the US Food and Drug Administration has approved Novavax’s Covid-19 vaccine, according to a letter from the agency, but only for people 65 and older and those 12 and up who have at least one underlying condition that puts them at higher risk of severe illness.

Novavax Inc. jumped in early trading after US regulators fully approved its Covid vaccine, easing investors’ concerns after the clearance was delayed and US Health and Human Services Secretary Robert F.