Novavax’s two-dose Covid-19 vaccine for adults ages 18 and older cleared a key step on the path toward Food and Drug Administration authorization on Tuesday.

The FDA’s committee of independent vaccine experts voted 21 to 0 with one abstention at the end of an all-day meeting to recommend authorizing the shot for use in the U.S. after an all-day public meeting in which it weighed safety and effectiveness data. The FDA usually follows the committee’s recommendations, though it is not obligated to do so. The agency could clear Novavax’s vaccine for distribution in the U.S. as soon as this week.

The Centers for Disease Control Prevention would still need to sign off on the shots before pharmacies and other health-care providers can start administering them to people.

Novavax’s shot would be the fourth Covid vaccine authorized for use in the U.S. and the first new one since the Johnson & Johnson vaccine was cleared in February 2021.

Novavax was one of the early participants in the U.S. government’s race to develop a Covid vaccine in 2020, receiving $1.8 billion in taxpayer funding from Operation Warp Speed. However, the company struggled for more than a year to get manufacturing in place and its clinical trial data appeared much later than Pfizer and Moderna.

Known technology

The Maryland biotech company’s shots are based on protein technology that’s been in use for decades in vaccines against hepatitis B and HPV. The technology differs from Pfizer and Moderna’s shots, which were the first ones using messenger RNA technology to receive FDA approval.

Dr. Peter Marks, who leads the FDA office responsible for reviewing vaccine safety and effectiveness, said Novavax’s vaccine would potentially appeal to unimmunized people who would prefer a shot that is not based on the mRNA technology used by Pfizer and Moderna. Though Johnson & Johnson’s shot is also available, the CDC has restricted its use due to a risk of blood clots, primarily in women.