Novavax’s Covid-19 vaccine was highly effective in preventing symptomatic infections, hospitalizations, and severe illnesses, long-awaited results from the company’s Phase 3 trial, released Monday, revealed. The vaccine was 90% protective against laboratory-confirmed symptomatic infection.
The trial results put this vaccine in the same efficacy ballpark as the mRNA vaccines produced by Pfizer-BioNTech and Moderna. But where those companies are currently producing and selling hundreds of millions of doses and are in the process of seeking full licensure from the Food and Drug Administration, Novavax still has steps it must take before it can apply to the regulatory authorizations it will need to start rolling out its vaccine.
“Today, Novavax is one step closer to addressing the critical and persistent global public health need for additional Covid-19 vaccines,” said Stanley Erck, the company’s president and CEO. “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.”
The results are in line with findings of an earlier, smaller trial Novavax conducted in the United Kingdom that was reported in January. And they are also in line with the performances of the mRNA vaccines already in use, said John Moore, an immunologist at Weill Cornell University.
“It is comparable in potency, efficacy to the Pfizer and Moderna vaccines,” said Moore, who was a participant in the Novavax trial.
The vaccine was 91% protective in people deemed to be at high risk of a bad outcome for a Covid-19 infection, including people over the age of 65, people with health conditions that increased their risk of severe Covid infection, and those in circumstances with frequent Covid exposure, the company reported.
Among the nearly 30,000 participants in the trial, which was conducted in the United States and Mexico, there were 77 confirmed cases of Covid — 63 in the placebo group and 14 in the vaccine arm. All of the cases in the vaccine group were mild. There were 10 moderate and four severe infections among placebo recipients. In a call with investors on Monday, the company revealed there were an additional six people who required hospitalization — one of whom died — in the placebo group. But they were not included in the efficacy analysis because the test results were not evaluated in the trial’s central laboratory.
The vaccine was tested in adults aged 18 and older. About 20% of the participants were Latin American, 12% African American, 7% Native American, and 5% Asian American. A placebo-controlled arm of the trial involving 2,248 adolescents and teens aged 12 to 17 is still underway.
The vaccine appeared to be well tolerated, with injection site tenderness or pain being the most common reported side effect. Adverse events were more frequent after the second dose, with about 40% of recipients reporting headache, muscle pain, and/or fatigue that lasted less than two days.
The company’s statement said the vaccine, currently known as NVX-CoV2373, was also 93% protective against so-called variants of concern and variants of interests — versions of the virus that have mutations which in some cases increase their transmissibility and/or their virulence. But most of the people in the study who were infected with one of the variants of concern were infected with the Alpha variant, also known as B.1.1.7, which was first discovered in the U.K. and is now the dominant virus in the U.S.
From the information released to date, it appears that none of the participants were infected with the worrying Delta variant, first spotted in India, so the vaccine’s performance against it remains in question. Very few of the infections were attributed to the Beta or Gamma variants, first seen in South Africa and Brazil, respectively.
The trials of the mRNA vaccines were completed before the variants of concern were first detected.
“All of these more resistant variants are going to cause a degree of loss of potency,” Moore said. “But with these strong vaccines, it’s not going to be wipe-outs.”
There have been high hopes for this vaccine, which can be stored at fridge temperature, making its distribution easier than that of the mRNA vaccines. The vaccine is given in two doses, three weeks apart.
The vaccine is a so-called recombinant protein vaccine, with the spike protein of the SARS-CoV-2 virus grown in moth cells. Those proteins are formed into nanoparticles, which are then mixed with an adjuvant, a compound that boosts the immune response to the vaccine.
The vaccine, which, if approved, would be Novavax’s first licensed product, is arriving late to the U.S. market, where there is currently enough vaccine available from three other authorized suppliers — Pfizer, Moderna, and Johnson & Johnson — to vaccinate all remaining eligible individuals. But the global need for additional vaccine sources remains high.
“Whether the demand is still there in the United States, that’s one thing. But we know that these companies are also looking at other parts of the world,” Norman Baylor, president and CEO of Biologics Consulting and a former head of the FDA’s Office of Vaccines, said earlier this month about the U.S. prospects for the Novavax vaccine.
“To me, it seems like it’s closing. Especially for adults,” Baylor said. “It will be tight in the United States. The global market, we do need additional vaccines.”
Novavax has entered into an agreement with Gavi, the Vaccine Alliance, to deliver 1.1 billion doses of its vaccine — once authorized for use — to the COVAX Facility, a partnership run by Gavi, the World Health Organization, and the Coalition for Epidemic Preparedness Innovations that is working to secure vaccines for countries around the world.