An Overview of the Novavax COVID-19 Vaccine

Novavax is a Maryland-based biotech company that has taken a traditional approach to developing a vaccine against COVID-19.

The company began a Phase 3 trial of its vaccine candidate, NVX‑CoV2373, in the United Kingdom in September 2020. This was followed by a second Phase 3 trial in the United States and Mexico in December 2020. These two late-stage trials enrolled a total of almost 50,000 people.

This put Novavax behind its competitors, but early results showed promise. The company announced the vaccine was 90% effective overall in the PREVENT-19 Phase 3 trial. And it was 100% effective against moderate and severe disease.

On August 19, 2022, the Food and Drug Administration (FDA) authorized the Novavax COVID-19 Vaccine, Adjuvanted for emergency use in individuals ages 12 and older. It is the first protein-based COVID-19 vaccine authorized in the U.S.

Novavax
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How It Works

The Novavax vaccine uses a custom-made spike protein that mimics the natural spike protein in the SARS-CoV-2 virus. Novavax has for years worked on developing its recombinant nanoparticle technology, and created the first COVID-19 vaccine using this method in the spring of 2020.

By summer 2020, early clinical trials showed that the vaccine appeared to be safe, and more advanced trials entered the planning stage in the United States and other countries.

The two-dose vaccine works by introducing a protein that prompts an antibody response, which blocks the ability of future coronavirus to bind to human cells and prevents infection. The protein is combined with Novavax’s Matrix-M adjuvant, which is important in enhancing the immune response elicited by the protein antigen.

How Effective Is It?

Early vaccine trial results published by Novavax revealed a strong antibody response to the vaccine in animals. By August 2020, early human trials showed strong antibody responses with no serious adverse events and few side effects.

Novavax announced on June 14, 2021, that the vaccine was 90.4% effective in a preliminary analysis of data from its Phase 3 trial in the U.S. and Mexico. It was also 100% effective against moderate and severe disease. The trial was conducted when the U.K. variant B.1.1.7, also known as the Alpha variant, was the predominant strain in the U.S.

This followed an announcement in late January that the vaccine was found to be 89.3% effective in its U.K. Phase 3 trial and included protection from the U.K. variant.

The company also announced that the vaccine was 60% effective in a Phase 2b clinical trial in South Africa and included protection from the South African variant B.1.351, also called the Beta variant.

In Novavax's trial, participants were not directly exposed to the virus, but instead researchers used a natural infection approach. This method was also used for the three COVID-19 vaccines that received approval or emergency use authorization (EUA) from the FDA.

When Will It Be Available?

Novavax's vaccine candidate generated a lot of interest because early animal study data showed that it was highly effective at preventing replication of the coronavirus in nasal passages. It was an important development for COVID vaccines since it suggested that it may help reduce both infection and transmission rates.

Novavax's vaccine also relies on an established delivery method and can be stored at standard refrigerator temperatures.

However, Novavax was behind its competitors when it came to clinical trials. Now that Novavax has received emergency use authorization from the FDA, it is now available and is being given to people in the U.S.

The U.S. has already secured 3.2 million doses of Novavax’s COVID-19 vaccine.

Throughout the development of their vaccine, Novavax has faced challenges and experienced significant delays due to manufacturing issues. Science magazine reported that the company had sold some of its manufacturing facilities and had to rely on more contractors to manufacture many of its vaccines. There were also delays in receiving authorization, as the FDA needed to review changes made to Novavax's manufacturing process.

Who Can Get the Novavax Vaccine?

According to the CDC, everyone 12 years and older is now eligible for the Novavax COVID-19 vaccine, which is given as a two-dose series, three to eight weeks apart.

In limited situations, people ages 18 years and older who have completed the primary COVID-19 vaccination and have not received any previous booster doses may receive a monovalent Novavax booster dose if they cannot receive an mRNA vaccine. This dose is given at least 6 months after completing the primary series. 

Novavax had announced on June 14, 2021, that it completed enrollment of 2,248 adolescents in its Phase 3 trial in adolescents ages 12 to 17. In February 2022, the company reported that the vaccine demonstrated 82% clinical efficacy against the Delta variant and planned to seek FDA authorization for this age group. Then on August 19, 2022, the FDA authorized the Novavax vaccine for individuals ages 12 years and older. Novavax also expects to initiate additional studies in younger children.

Side Effects and Adverse Events

Adults who took part in Novavax's Phase 3 trials were asked to record any local or systemic reactions after each dose of the vaccine.

The most commonly reported side effects were:

  • Injection site pain, swelling, and redness
  • Fatigue
  • Muscle pain
  • Headache
  • Joint pain
  • Nausea/vomiting
  • Fever
  • Chills

Injection site pain lasted less than three days and fatigue, headaches, or muscle pain lasted less than two days in the Phase 3 trials.

Although rare, hypersensitivity reactions, lymphadenopathy-related reactions, myocarditis, and pericarditis were also reported in some people who received the Novavax vaccine.

Funding and Development

Novavax has been awarded more than $2 billion globally for its efforts to develop a COVID-19 vaccine, with $1.6 billion from the U.S. government alone. The U.S. funds were given as a part of Operation Warp Speed and from the Biomedical Advanced Research and Development Authority (BARDA). BARDA is a program of the Department of Health and Human Services. This program and Operation Warp Speed sought to speed up how quickly vaccines to fight COVID-19 can be developed and approved for use.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Food and Drug Administration. FDA Roundup: August 19, 2022.

  3. Novavax. Novavax investigational COVID-19 vaccine (NVX-CoV2373).

  4. Novavax. Novavax COVID-19 vaccine demonstrates 89.3% efficacy in UK phase 3 trial.

  5. UC Davis Health. UC Davis Health joins Novavax in testing a new COVID-19 vaccine.

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  7. Food and Drug Administration. Fact sheet for healthcare providers administering vaccine (vaccination providers): emergency use authorization (EUA) of the Novavax COVID-19 vaccine, adjuvanted to prevent coronavirus disease 2019 (COVID-19).

  8. Department of Health and Human Services. Biden-Harris Administration secures 3.2 million doses of Novavax COVID-19 vaccine.

  9. Wadman M. Will a small, long-shot U.S. company end up producing the best coronavirus vaccine? Science. doi:10.1126/science.abf5474

  10. Centers for Disease Control and Prevention. Stay Up to Date with COVID-19 Vaccines Including Boosters.

  11. Centers for Disease Control and Prevention. Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Approved or Authorized in the United States.

  12. Food and Drug Administration. FDA Roundup: August 19, 2022

  13. Novavax. Novavax Announces Initiation of Phase 2b/3 Hummingbird™ Global Clinical Trial for the Novavax COVID-19 Vaccine in Children Aged Six Months Through 11 Years.

  14. Department of Health and Human Services. HHS, DOD collaborate with Novavax to produce millions of COVID-19 investigational vaccine doses in commercial-scale manufacturing demonstration project.

By Rachael Zimlich, BSN, RN
 Rachael is a freelance healthcare writer and critical care nurse based near Cleveland, Ohio.