Five vaccine vials in a row.
Illustration: PGN

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What you need to know

  • The CDC recommended the two-dose Novavax COVID-19 vaccine for adults following FDA authorization. The vaccine is authorized as a primary series vaccine, but it has not yet been authorized as a booster.
  • There are some concerns around the risk of heart inflammation. People remain more likely to develop this condition from COVID-19 infection than from COVID-19 vaccination.
  • Novavax can help fill in the gaps of the COVID-19 vaccination campaign.

Novavax’s COVID-19 vaccine is the fourth vaccine to receive emergency use authorization in the U.S. The majority of adults in the country are already vaccinated, but the Novavax vaccine could play a critical role in filling remaining immunization gaps.

How effective is the Novavax vaccine?

Clinical trials found that the Novavax vaccine is 90 percent effective at preventing infection from older COVID-19 variants and 100 percent effective at preventing severe disease. There were no cases of moderate or severe infection among trial participants who received the vaccine. 

The clinical trials took place before Omicron became the dominant variant, so it’s unclear how the Novavax vaccine will fare against current strains of the virus. The company did publish a lab study in December that showed people who received two Novavax doses had an immune response against Omicron. However, the number of antibodies dropped about fourfold against Omicron compared to the original virus strain. A Novavax booster was able to raise antibody levels back up by ninefold.

How is the Novavax vaccine different from the mRNA and Johnson & Johnson shots? 

Novavax uses a protein-based technology in its vaccine. This means its design is different from that of the Pfizer, Moderna, and Johnson & Johnson COVID-19 shots. Protein-based technology has been used for decades, including in vaccines against influenza, hepatitis B, HPV, and shingles. For people who are allergic to the ingredients used in mRNA vaccines, the Novavax vaccine serves as a crucial option.

What are the side effects of the Novavax vaccine?

The most common side effects are injection site pain, fatigue, headache, and muscle pain. In about 1 million doses of the vaccine given in other countries, Novavax said that it found 17 likely cases of myocarditis and pericarditis, both forms of heart inflammation.

Heart inflammation has been an extremely rare, but at times serious, side effect of other COVID-19 vaccines. People remain more likely to develop these conditions from COVID-19 infection than from COVID-19 vaccination. Nevertheless, it’s important for regulatory agencies to warn the public about such risks.

When will the Novavax vaccine become available?

The Novavax vaccine will become available in the U.S. in the coming weeks.