FDA authorizes Novavax as new alternative to mRNA COVID-19 vaccines

The Food and Drug Administration has granted Novavax's COVID-19 vaccine emergency use authorization, paving the way for a new fourth option for the 10% of American adults who have yet to receive at least one dose of any other shot.

"Today's authorization offers adults in the United States who have not yet received a COVID-19 vaccine another option that meets the FDA's rigorous standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization," said FDA Commissioner Dr. Robert Califf in a release on Wednesday. 

Like the other available COVID-19 vaccines, Novavax's shots will need to be formally recommended by the Centers for Disease Control and Prevention before they can be made available. That could happen as soon as next Tuesday, when the agency's outside vaccine advisers are next scheduled to meet. 

The FDA's decision comes more than a month after the vaccine earned the near unanimous backing of the regulator's own panel of outside advisers. 

"The American public can trust that this vaccine, like all vaccines that are used in the United States, has undergone the FDA's rigorous and comprehensive scientific and regulatory review," said the FDA's Dr. Peter Marks.

At their June 7 meeting, FDA officials had said the agency was still in the midst of vetting the company's process for manufacturing and checking the quality of shots – an issue that the company's executives acknowledged was one of the biggest obstacles to completing its submission to the regulator.

"What really took the longest time, however, wasn't the manufacturing of the product. It was the generation of the assays to illustrate that we could make the product over and over again, the same way, and to deploy those assays against the multiple lots," said Novavax's Filip Dubovsky.

Some 3.2 million doses of Novavax's vaccine have been secured by the Biden administration. The company is among the original roster of Operation Warp Speed contracted vaccines from 2020.

But it's unclear when or how many of those doses will be initially available for states and pharmacies to order. The Department of Health and Human Services said Monday that it is still conducting quality testing of the Novavax vaccine.

In clinical trials conducted before the Omicron variant, Novavax was found to have 90.4% efficacy in preventing any symptomatic COVID-19 infections and as much as 100% efficacy against moderate-to-severe disease.

A spokesperson for the Department of Health and Human Services did not return a request for comment.

The FDA also said last month it was at loggerheads with Novavax over whether to attach a warning of myocarditis potentially linked to the shots. This type of heart inflammation side effect has also been noted by the CDC as a "rare risk" associated with the mRNA vaccines from Pfizer-BioNTech and Moderna, according to multiple studies. 

The fact sheets authorized for Novavax's shots will ultimately include the warning, the FDA said.

Novavax has otherwise touted its use of older vaccine technology for its COVID shot as a good alternative to the country's stable of effective vaccines because it has been administered with fewer side effects during trials than the Pfizer or Moderna shots. 

The Novavax vaccine works by giving the immune system a piece of the virus grown in insect cells and mixed with an ingredient – called an adjuvant – derived from tree bark that aims to boost its effectiveness in the body. 

The mRNA vaccines that are already available work by providing cells with a blueprint to create spike proteins to trigger an immune response from the body. Novavax, on the other hand, includes the proteins in its vaccine. This kind of technique, called protein subunit vaccines, has long been used widely in other shots.

Novavax's vaccine might also overcome some religious objections that have been lodged over how the Moderna and Pfizer-BioNTech shots were initially studied.

Early in their development, studies of those two vaccines included testing on a controversial cell line linked to an abortion in the 1970s that is widely used in medical research – though neither shot ultimately uses any fetal tissue in manufacturing their vaccines. Johnson & Johnson's Janssen vaccine uses a cell line that was originally developed from an abortion.

"No human fetal-derived cell lines or tissue, including HEK293 cells, are used in the development, manufacture or production of the Novavax COVID-19 vaccine candidate, NVX-CoV2373," Alison Chartan, a spokesperson for Novavax, told CBS News last month.

Like the mRNA vaccine makers, Novavax says it is also studying a version of its shots redesigned to target the BA.4 and BA.5 subvariants of Omicron now dominant across the country. The first data on those shots are expected "in the late summer or fall," the company says.

However, Novavax has argued that "there continues to be a role" for the current version of its vaccine.

The company has said it plans to pursue an authorization for its current vaccine to be used as a booster shot as well. It is also trialing mix-and-match boosting with its vaccine in people who initially received a Pfizer or Moderna primary series.

"Our vaccine has been demonstrated to be efficacious against variants, induces broad immune responses against Omicron variants, and this may be the best choice for people who prefer a vaccine with an extensive safety and efficacy database," Novavax's Gregory Glenn told the FDA's advisers at a meeting in late June.