Did US FDA authorize Novavax COVID-19 shots? Properties of updated protein-based vaccine explored

The U.S. Food and Drug Administration (FDA) approved the use of the Novavax COVID-19 Vaccine, Adjuvanted (2023-2024 Formula) (NVX-CoV2601) on Tuesday, October 3, 2023. The authorization allows the shot to be used as a booster for all individuals aged 12 and older and will soon be made available at local pharmacies and doctors' offices.

With this vaccine being its sole product, the Gaithersburg, Maryland, company is counting on its sales to remain financially solvent. Following Tuesday's approval, the company's shares climbed more than 11%.

The vaccine is effective against the EG.5 strain, which is currently dominant in the United States, and is also updated to target the XBB Omnicron subvariant. What's interesting about Novavax's shot is that it uses a traditional protein-based technology, unlike its contemporaries, the Pfizer-BioNTech and Moderna vaccines, which use mRNA (messenger RNA) technology.

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Novavax's original COVID-19 vaccine was approved in July 2022

Novavax's original shot received U.S. authorization in July 2022, long after that of Pfizer and Moderna, which were already being administered. The Maryland-based company also missed out on the vaccine windfall enjoyed by its mRNA counterparts. This is in part due to the delayed filing for approval resulting from manufacturing issues. However, another reason is its protein-based technology, which takes longer to be developed.

According to the Mayo Clinic, an mRNA-based vaccine gives one's cells instructions on how to make the Spike protein (S protein) found on the surface of a virus. When injected, one's immune cells begin making the s protein and displaying it on the cell's surface, promoting the body to create antibodies that would fight the COVID-19 virus.

Whereas protein-based vaccines, or protein subunit vaccines, inject harmless spike protein material directly into the body, which in turn creates antibodies and defensive white blood cells. If one becomes infected with COVID-19, the antibodies will fight the virus. Sometimes it includes an "adjuvant," an added ingredient that boosts its effects.

The mRNA technology was never used in a vaccine before the pandemic, even though it had been in development for years. However, due to its quick development time of about six weeks, it became of key importance during the pandemic. On the other hand, a protein-based vaccine takes longer to manufacture. In the case of Novavax, it takes about four months.

According to John Moore, a virologist at Cornell University, getting either type of vaccine would not make a difference to the body's immune response.

As per the factsheet for the Novavax COVID-19 vaccine, spike protein is produced from baculovirus-infected Sf9 cells (fall armyworm), and adjuvant is derived from saponin extracts from the soapbark tree. Other ingredients include cholesterol, phosphatidylcholine, potassium dihydrogen phosphate, potassium chloride, disodium hydrogen phosphate dihydrate, sodium chloride, disodium hydrogen phosphate heptahydrate, sodium dihydrogen phosphate monohydrate, and polysorbate 80.

Additionally, trace amounts of baculovirus, insect cell proteins, and DNA may also be present.

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Despite making up only 0.01% of all COVID-19 vaccines (as per data released by the government in May 2023), the CDC's (Centers for Disease Control) Advisory Committee on Immunization Practices (ACIP) last month acknowledged the need for alternatives to mRNA-based vaccines. This comes after concerns about the possible side effects of mRNA vaccines.

At the time, the Maryland-based company's updated shot did not have the FDA's approval. However, the company presented its data to the committee.

ACIP also released a COVID-19 vaccine recommendation list, which included "those expected to be licensed or authorized (by the FDA) in the coming months." According to a press release by Novavax, its vaccine has been authorized for emergency use by the FDA (EUA). Therefore, NVX-CoV2601 does not need separate endorsement by the CDC.