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Novavax vaccine shows strong protection against COVID-19

The protein-based vaccine was more than 90% effective at preventing COVID-19 in a Phase 3 trial

by Ryan Cross
June 17, 2021 | A version of this story appeared in Volume 99, Issue 23

A photo of a participant in the Novavax clinical trial receiving a shot
Credit: Matt Feldman/Novavax
A participant in Novavax’s Phase 3 trial gets a shot in Plano, Texas.

Novavax has joined the growing ranks of vaccine developers with safe and effective shots for preventing COVID-19. The firm says its vaccine was 90.4% effective at preventing any form of the disease, and 100% effective at preventing moderate and severe disease, in a Phase 3 clinical trial of nearly 30,000 people in the US and Mexico.

The shot won’t be available until later this year. Novavax expects to file its data with regulators, including the US Food and Drug Administration, in the third quarter.

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“I am glad that we will have yet another vaccine to deploy,” says Tony Moody, an immunologist at the Duke Human Vaccine Institute. Even though the US “is in a good place now,” he notes that other countries, such as India, need more vaccines. Novavax aims to produce 100 million doses per month by the end of September and 150 million by the end of December.

Novavax was one of the first companies to announce that it would work on a vaccine for the novel coronavirus in January 2020. That vaccine now stands to become its first commercial product.

The Gaithersburg, Maryland-based company has struggled since its founding in 1987 to develop a successful vaccine. After a disappointing clinical trial in 2016, workforce cuts, and the sale of its manufacturing facilities, Novavax’s stock was trading for less than $4 a share in early 2020. Then a $1.6 billion investment in vaccines by the US government provided an opportunity for a dramatic turnaround.

On June 16, two days after announcing its Phase 3 results, the company’s stock was trading at about $175 a share—valuing it at about $13 billion.

The Novavax shot is the first protein-based COVID-19 vaccine to complete clinical trials. Moody calls it a “more traditional approach,” akin to a hepatitis B vaccine. Novavax uses moth cells to produce SARS-CoV-2 spike proteins, which are then embedded in nanoparticles made of detergent micelles and a tree-derived adjuvant called saponin.

The vaccines made by AstraZeneca, Johnson & Johnson, Moderna, and Pfizer are based on newer technologies that use either messenger RNA or adenoviral vectors to deliver the genetic instructions for making the spike protein into our cells.

Novavax said its vaccine was 93% effective at protecting against variants of the virus, although the majority of COVID-19 cases reported in its Phase 3 trial were due to the Alpha variant—first detected in the UK—which hasn’t posed a problem for approved vaccines so far.

In January, Novavax said its shot was only 49% effective in a smaller clinical trial in South Africa where the Beta variant was widely circulating. The firm’s larger trial in the US and Mexico only detected the more worrying Beta variant in two cases, and the Delta variant—first detected in India—in one case. Scientists say it is too soon to draw conclusions about how the shot will hold up if these variants become more common.


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