Novavax COVID-19 Vaccine is 90 Percent Effective, Trial Shows

The coronavirus vaccine is expected to help meet urgent global need.

person getting vaccinated

Updated on June 14, 2021.

The Novavax COVID-19 vaccine has an overall efficacy rate of 90.4 percent, according to the company’s Phase 3 trial results. The vaccine, which requires two doses given 21 days apart, could become the fourth coronavirus vaccine available in the United States.

The late-stage trial is ongoing, but the U.S. biotech firm says it plans to request emergency use authorization (EUA) of its vaccine, called NVX-CoV2373, from the U.S. Food and Drug Administration (FDA) in the next few months.

The Novavax trial results, which will also be submitted to peer-reviewed journals for publication, also showed that its vaccine was:

  • 91 percent effective in high-risk groups
  • 93 percent effective against worrisome variants
  • 100 percent effective in preventing moderate or severe disease

"Today, Novavax is one step closer to addressing the critical and persistent global public health need for additional COVID-19 vaccines. These clinical results reinforce that NVX-CoV2373 is extremely effective and offers complete protection against both moderate and severe COVID-19 infection," said Stanley C. Erck, Novavax's president and chief executive officer, in a June 14 news release. "Novavax continues to work with a sense of urgency to complete our regulatory submissions and deliver this vaccine, built on a well understood and proven platform, to a world that is still in great need of vaccines."

More about the Phase 3 trial

The Novavax study enrolled 29,960 participants age 18 and older across 119 sites in the U.S. and Mexico. Some of the volunteers received the vaccine while others were given a placebo. Of these people, 77 were diagnosed with COVID-19. Of these cases, 63 were in the placebo group and 14 had received the vaccine. All coronavirus infections among the vaccine group were mild. Meanwhile, there were 10 moderate and four severe cases among the placebo group. The company noted that most cases were identified among people considered to be at high-risk for the infection, including those older than 65-years of age, those with underlying health issues and those with repeated exposure to the virus.

Among the 77 COVID-19 infections, the researchers examined sequencing data for 54 cases. The researchers concluded the vaccine was highly effective, 93.2 percent, against known variants of concern.

The vaccine was well-tolerated among the study participants. Commonly reported side effects included pain at the injection site, fatigue, muscle pain and headache. These issues resolved within two days, Novavax reported.

How the vaccine works

Novavax's coronavirus vaccine works differently that the Pfizer and Moderna mRNA vaccines and the one-dose Johnson & Johnson vaccine.

It relies on recombinant nanoparticle technology and Novavax's adjuvant (a substance that helps prompt an immune response in the body), called Matrix-M.

Recombinant protein vaccines aren’t new. They’ve been used for decades. Another example is the hepatitis B vaccine. They work by teaching the immune system to recognize a virus by exposing it to a laboratory-made version of a viral protein.

By comparison, mRNA vaccines use genetic material to carry the genetic instructions that will stimulate an immune response. The Johnson & Johnson vaccine uses a weakened cold virus to deliver the instructions.

What about storage?

The Novavax vaccine is stored and stable at 35° to 46°F, which means that existing vaccine supply chain channels can be used for its distribution. It is also packaged in a ready-to-use liquid formulation.

Similarly, the Johnson & Johnson vaccine remains stable (and effective) for three months at 35-46° F.

Moderna’s vaccine, on the other hand, remains stable for 30 days at 36° to 46°F. At a colder temperature of -4°F, the Moderna vaccine could remain stable for up to six months.

Meanwhile, Pfizer’s vaccine must be stored in an ultra or deep freezer at between -112 and -76° F in order to remain effective. Before mixing, however, the vaccine may be stored in the refrigerator for up to 31 days at between 36 and 46° F, according to the CDC.

What happens now?

Novavax says it plans to apply for authorization in the United States and is on track to produce 100 million doses per month by the end of September and 150 million doses per month by the end of 2021.

Teen trials of the Novavax vaccine, involving young people between 12 and 17-years old, are also already underway with 2,248 participants enrolled as of mid-June.

But even if the Novavax shot becomes the fourth coronavirus vaccine to get a green light in the United States, it’s likely that its impact will be greatest in other parts of the world.

Novavax’s shot is one of six experimental vaccines the U.S. government supported, investing $1.6 billion in the ongoing research and preordering 100 million doses.

In May, however, Novavax, announced that it finalized an advance purchase agreement (APA) with Gavi, the Vaccine Alliance (Gavi) for supply of its vaccine to the COVAX Facility, which was created to rollout vaccines equally among participating countries. In 2020, 57 countries were eligible to apply for new vaccine support from Gavi, including Afghanistan, Bangladesh, Cambodia, India, Pakistan and Ethiopia.

"This is a tremendous opportunity to partner with global organizations focused on accelerating equitable access to safe and effective COVID-19 vaccines, particularly in countries where vaccination rates are currently low," said Erck in a May news release. "This arrangement is the culmination of a collaboration among CEPI, Gavi, Serum Institute and Novavax, who are partnering in our urgent mission to deliver significant amounts of vaccines to all countries, regardless of income level.”

Article sources open article sources

Novavax. “Novavax COVID-19 Vaccine Demonstrates 90% Overall Efficacy and 100% Protection Against Moderate and Severe Disease in PREVENT-19 Phase 3 Trial.” Jun 14, 2021.
U.S. National Institutes of Health. “Phase 3 trial of Novavax investigational COVID-19 vaccine opens.” Dec 28, 2020.
U.S. National Institute of Allergy and Infectious Diseases. “Vaccine Types.” Jul 1, 2019.
Novavax. “Novavax Announces $1.6 Billion Funding from Operation Warp Speed.” Jul 7, 2020.
Novavax, “Novavax and Gavi Execute Advance Purchase Agreement for COVID-19 Vaccine for COVAX Facility.” May 6, 2021.
Gavi. “Eligibility.” Aug 26, 2020.

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