What Happened to the Novavax Vaccine?

In June, MedPage Today wrote about whether Novavax and its "tried-and-true" subunit protein approach to a COVID-19 vaccine could potentially ease vaccine hesitancy. In this story, we explore what's known about the vaccine and why it still isn't on the market.

Pfizer, Moderna, and Johnson & Johnson: Ask any American, and they'll likely be able to rattle off the trio of COVID-19 vaccines available in the U.S.

But what about Novavax's "tried and true" protein subunit vaccine?

Early this year, public health experts told MedPage Today that Novavax -- whose vaccine strategy is used in other vaccines on the market today -- could provide another option to reach the vaccine hesitant.

The recombinant nanoparticle technology used in Novavax's protein subunit vaccine candidate (known as NVX-CoV2373) generates full spike protein, and the vaccine is formulated with an adjuvant to enhance immune response and stimulate high levels of neutralizing antibodies, according to the company.

The technology is the same as that used in the Flublok influenza vaccine, and is similar to other vaccines that have been around for a long time, like the hepatitis B vaccine.

However, nearly a year later, the Novavax vaccine still isn't available in the U.S. In August, Novavax announced that it was delaying submission of an emergency use authorization (EUA) to the FDA until the fourth quarter.

On December 15, full results from PREVENT-19, Novavax's pivotal phase III trial of its vaccine, were published in the New England Journal of Medicine.

The company said in an announcement that the trial achieved its primary endpoint of preventing infection at least 7 days after the second dose. Overall efficacy was 90.4% and efficacy against moderate-to-severe disease was 100%. Adverse events were mostly mild to moderate and transient. Severe reactions were infrequent, and there were no safety concerns related to vaccination.

Novavax did not immediately make a member of leadership available for an interview following the publication of the study. However, a spokesperson told MedPage Today in an email that it expects to submit its complete chemistry, manufacturing, and controls data package to the FDA by the end of 2021.

"We still anticipate a significant market need in the U.S. and globally," the spokesperson said.

At the same time, with the mRNA vaccines already saturating the market, it's not entirely clear how the Novavax vaccine will be rolled out or how it will resonate with consumers in the U.S., should it be granted an EUA from the FDA.

Mayank Mamtani, MSc, a senior biotech analyst and head of healthcare research at B. Riley Securities, told MedPage Today that the way to think about the vaccine is as an alternative to the mRNA vaccines. It is a "very strong vaccine," and while it may come late in the game, it has been differentiated, he noted.

"This is a very attractive option to have," he added.

In a December 16 research note, Mamtani wrote that NVX-CoV2373 is "well-suited for COVID's likely evolution into a relatively benign flu-like paradigm," adding that prior NEJM publications included datasets clinically validating that the Novavax platform "maintain[ed] high efficacy despite antigenic drifts, including via the adjuvant-specific effect."

"We view tolerability profile of a vaccine candidate to be a key consideration for use in a post-pandemic environment, where [Novavax] continues to stand out as the least reactogenic vaccine," he wrote.

The Novavax vaccine has made significant strides in other countries.

On December 20, the company announced that the European Commission had granted the vaccine conditional marketing authorization in people 18 and older. They noted that it had recently received an EUA in Indonesia and the Philippines, where it will be commercialized under the trade name Covovax. Covovax also received an emergency use listing from the WHO.

One day later, Novavax said it had initiated a booster study.

The vaccine's extended stability and simple storage requirements of up to 6 months at refrigerator temperatures make it "well suited for global deployment," according to the authors of the NEJM study.

"The efficacy of NVX-CoV2373 in preventing moderate-to-severe COVID-19 as well as any symptomatic COVID-19 in people at high risk for acquisition and complications of COVID-19 will make this vaccine a valuable tool in controlling the pandemic and its most serious health and economic consequences," they wrote.

Even with the trial's promising results, the question remains as to whether the Novavax vaccine will reach more of the vaccine hesitant in the U.S.

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