WASHINGTON (AP) -- The Food and Drug Administration has issued a long-awaited approval of Novavax's COVID-19 vaccine but with unusual restrictions.

Novavax makes the nation's only traditional protein-based coronavirus vaccine - and until now it had emergency authorization from FDA for use in anyone 12 and older.

But late Friday, the FDA granted the company full approval for its vaccine for use only in adults 65 and older - or those 12 to 64 who have at least one health problem that puts them at increased risk from COVID-19.

Vaccines made by Novavax's competitors Pfizer and Moderna already are fully licensed for use in anyone 12 and older, and also are authorized for use in children as young as 6 months.

Next month, influential advisers to the Centers for Disease Control and Prevention were set to debate if yearly COVID vaccines still should be recommended for everyone or only certain people at higher risk. The Novavax decision suggests the Trump administration may already have decided how to proceed in advance of that meeting.

Novavax chief executive John C. Jacobs welcomed the licensure.

"Market research and U.S. CDC statistics indicate that older individuals and those with underlying conditions are the populations most likely to seek out COVID-19 vaccination seasonally. This significant milestone demonstrates our commitment to these populations and is a significant step towards availability of our protein-based vaccine option," he said.

In its Friday approval letter, the FDA didn't explain the restrictions although they reflect skepticism about vaccines from Health Secretary Robert F. Kennedy Jr. and other Trump officials.

Novavax originally showed its vaccine was safe and effective in a 30,000-person clinical trial. The FDA had been on track to grant Novavax full approval - without restrictions -- by its April 1 target date, according to two people with direct knowledge of the situation who spoke on condition of anonymity to discuss confidential agency matters.

Novavax later announced the FDA instead was asking it to run an additional trial after approval, which is highly unusual. FDA did order several additional trials to be completed in the next few years, some examining whether the vaccine might be associated with some heart conditions. Another required study must assess the benefits of continuing vaccination in 50- to 64-year-olds who don't have health problems that increase their risk from COVID-19.

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