ABOVE: A shipment of Novavax COVID-19 vaccines in a Netherlands warehouse NOVAVAX

Update (October 20): The US Food and Drug Administration granted an emergency use authorization for a booster dose of Novavax’s COVID-19 vaccine yesterday. The booster is available to adults 6 months after they have completed their primary vaccination series with any authorized or approved COVID-19 vaccine.

Update (July 20): On Tuesday (July 19), the US Centers for Disease Control and Prevention officially endorsed Novavax’s COVID-19 vaccine for use in adults. “If you have been waiting for a COVID-19 vaccine built on a different technology than those previously available, now is the time to join the millions of Americans who have been vaccinated,” CDC Director Rochelle Walensky says in the agency’s media statement.

On Wednesday (July 13), the US Food and Drug Administration granted an emergency use authorization for the COVID-19 vaccine developed by the Maryland-based biotech firm Novavax. If the Centers for Disease Control and Prevention (CDC) recommends the two-dose, protein-based vaccine, it will become freely available to the country’s adults sometime in the next few weeks.

“Authorizing an additional COVID-19 vaccine expands the available vaccine options for the prevention of COVID-19, including the most severe outcomes that can occur such as hospitalization and death,” FDA Commissioner Robert Califf says in an agency statement about the decision. The Novavax shot is already authorized in more than 40 other countries and by the World Health Organization, according to Science.

The now-authorized two doses of the vaccine, which are administered three weeks apart, consist of SARS-CoV-2 spike proteins produced by insect cells as well as an adjuvant derived from the bark of the soapbark tree that enhances the immune response, the statement explains. So instead of delivering the mRNA instructions for making spike proteins, like currently available vaccines from Moderna and Pfizer/BioNTech do, it delivers the proteins directly to mimic infection and generate future protection against the virus. Similar tech has been employed in vaccines for years, including in vaccines for human papillomavirus (HPV) and hepatitis B. Novavax says the shots also perform well as boosters, and that the company will pursue authorization for that use in the near future, according to The New York Times.

See “The Promise of mRNA Vaccines

Since it does not contain the lipid nanoparticles linked to COVID-19 vaccine allergies, the vaccine could be an option for people who had poor reactions to the prevailing mRNA-based choices and who are concerned about the Johnson & Johnson vaccine’s safety, multiple outlets report. According to Novavax,  the US government has ordered 3.2 million doses of the vaccine.

FDA advisers say they hope that the option of a more conventional vaccine—as opposed to the novel technologies used in the vaccines available currently—may help sway the roughly 25 percent of American adults who remain unvaccinated, according to STAT. “We do have a problem with vaccine uptake that is very serious in the U.S., and anything we can do to make people more comfortable to accept these potentially lifesaving products is something we are compelled to do,” Peter Marks, the director of the FDA’s Center for Biologics Evaluation, said at a June 7 Vaccines and Related Biological Products Advisory Committee meeting where FDA advisers voted 21-0 (with one abstention) in favor of granting an emergency use authorization.

The vaccine’s delayed authorization stems from its complex production process, The Washington Post reports. However, experts speculate that its protein-based technology may prove advantageous against Omicron and its subvariants. Indeed, data presented to FDA advisors suggest the Novavax vaccine provides better protection than the mRNA vaccines against newer subvariants, including BA.5. “The Novavax data was pretty significant,” FDA adviser and professor of cancer immunology and virology at Dana-Farber Cancer Institute Wayne Marasco tells the Post. “I wonder if we’re not witnessing some of the limitation that there may be [of] the mRNA vaccines. Yes, they were first out of the gate. But they don’t appear to have that breadth of protection.”

See “COVID-19 Vaccine Combos Aim to Boost Immunity