FDA Approves Novavax’s COVID-19 Vaccine With Restrictions

On May 16, 2025, the U.S. Food and Drug Administration (FDA) approved licensure of Novavax, Inc.’s Nuvaxovid protein-based COVID-19 vaccine, which has been available in the United States under Emergency Use Authorization (EUA) since July 2022.¹ The decision for a full licensure was postponed while  the new agency leadership under the current administration conducted a more thorough review of COVID vaccines.²

In its approval letter to Novavax, the FDA granted a license authorizing the company to manufacture and distribute Nuvaxovid. The agency stated that the vaccine is indicated to prevent COVID-19 disease caused by SARS-CoV-2 virus in adults ages 65 and older. The FDA also indicated that the vaccine is approved for individuals aged 12 to 64 years old with at least one underlying condition that increases their risk of severe COVID outcomes.³

In response to the approval with restrictions, Novavax president and CEO John Jacobs said, “Market research and U.S. CDC statistics indicate that older individuals and those with underlying conditions are the populations most likely to seek out COVID vaccination seasonally.”⁴

Novavax Required to Conduct Post-Marketing Studies Amid Heightened Vaccine Review

To continue monitoring the safety of Nuvaxovid after its approval, the FDA has required Novavax to complete the following studies:⁵

1. Pregnancy and Infant Outcomes Study
   This study will track the health of pregnant women who receive the Novavax COVID-19 vaccine, along with the health of their babies after birth. It will determine whether the vaccine is safe to use during pregnancy. The final report is due by June 30, 2027.

2. Heart and Stroke Risk Study (UK)
   In the United Kingdom, researchers are studying whether the vaccine is linked to heart rhythm problems (atrial fibrillation) or strokes. The study uses patient health data to monitor any possible risks. The final report is due by June 30, 2028.

3. Heart and Stroke Risk Study (United States)
   This U.S. based study evaluates whether people aged 12 and older face any increased risk of heart rhythm issues or strokes after receiving the vaccine. The final report is due by September 30, 2028.

4. Phase 4 Study on Vaccine Safety and Effectiveness in Low Risk Adults (Ages 50–64)
   The FDA has directed Novavax to conduct a new randomized, double-blind, placebo-controlled, post-marketing Phase 4 trial to evaluate the safety and effectiveness of Nuvaxovid in adults ages 50 to 64 who are not considered high-risk. Although late stage trials in 2021 showed the vaccine to be about 90 percent effective, FDA Commissioner Martin Makary, MD, MPH, questioned whether that data still applies, emphasizing that new biological products must undergo new clinical studies.

Novavax Highlights Potential Side Effects and Safety Precautions for Nuvaxovid

In a recent press release, Novavax highlighted several important side effects and precautions associated with Nuvaxovid. The company emphasized that immediate medical treatment must be available to manage any severe allergic reactions (anaphylaxis) that could occur following vaccination.⁶

Novavax also noted that clinical trials have shown an increased risk of heart inflammation (myocarditis) and inflammation around the heart (pericarditis) after receiving the vaccine. There have been additional reports of these conditions after the vaccine was made available to the public. The CDC has published guidelines for individuals who have a history of heart problems.⁷

Another potential side effect is fainting (syncope), which can happen with many injectable vaccines, including Nuvaxovid. The company states that proper procedures should be in place to prevent injury in case of fainting. Additionally, people with weakened immune systems, such as those receiving immunosuppressive treatment, may not have as strong a response to the vaccine. Novavax also acknowledged that vaccine may not provide full protection for everyone who receives it.⁸

Common side effects after receiving the vaccine include pain or tenderness at the injection site, headaches, muscle aches, fatigue, and fever.⁹

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