
Novavax says its vaccine is 80% effective in teens, but manufacturing questions continue to cloud future
Novavax finally submitted an application for emergency use authorization for its Covid-19 vaccine late last month. Now a second application may already be in the offing.
The oft-delayed but never-boring Maryland-based vaccine company announced positive results from its adolescent trial on Thursday. The biotech’s vaccine, known as Nuvaxovid, was 80% effective at preventing symptomatic disease in patients 12 to 17 years old.
The 2,247-person trial was conducted while the Delta variant — significantly more infectious and slightly evasive to immune responses against the original virus — was dominant in the US. The company said it sequenced 11 out of 20 confirmed Covid-19 cases in the trial; all were Delta.
The volunteers also showed about 50% more neutralizing antibodies as adults had in previous trials, meeting an FDA requirement for non-inferiority.
The new data raise the prospect that a third vaccine could become available for teenagers in the US and other parts of the world, joining the mRNA shots from Pfizer and Moderna. Although those doses have been available for months in the US, vaccination rates for teenagers remain low relative to adults: Just 57% of Americans between 12 and 17 have received at least 2 doses, according to the New York Times tracker, compared with 71% of 18 to 65 year-olds and 89% of those over 65.
Novavax has long argued its protein-based shot could be more attractive for some people, particularly the vaccine-hesitant, than mRNA shots: Its technology is older and used in other shots, they note, and it has a lower side effect profile.

Those same factors, they argued, could make Nuvaxovid an attractive option in helping vaccinate teens, although it’s not clear whether the shot is sufficiently less reactogenic than mRNA to boost uptake.
Around half of the vaccinated volunteers each reported muscle pain, fatigue and headache. In Moderna’s adolescent trial, by contrast, those symptoms each appeared in about 70% of vaccinated participants. (Novavax did not release precise breakdowns, opting for a graph instead.)
”We believe that our efficacy and safety profile will make us a desirable option in the pediatric population,” Silvia Taylor, Novavax’s VP of corporate affairs, told reporters Thursday.
Novavax has also made large commitments to distributing its vaccine around the world at a time when vaccine access is still inequitable.
But the company’s plans for kids will face the same hurdles as the company’s plans have faced in adults.
For one, the Omicron variant has made its shot significantly less effective, although like its mRNA rivals, the company has shown that a booster shot at least temporarily recoups much of the lost activity. And the company showed data Thursday that antibodies teenagers developed from the shot were able to neutralize Omicron, albeit at reduced potencies.
And then there’s manufacturing: The company struggled for nearly a year and a half to reliably produce its shot at scale, although there are signs those issues are finally abating. The vaccine is now authorized by the WHO and European regulators and is also entering use in the UK, Indonesia, India and other parts of the globe.
Although the FDA has yet to issue a decision on Novavax’s shot, the company’s choice to submit an EUA suggests it believes that the manufacturing issues that repeatedly delayed authorization have been resolved.
Nevertheless, Reuters reported this week that Novavax has delayed shipments to Europe and other parts of the globe. The Philippines, for example, said it has not received a single one of the 30 million shots it ordered and was now considering renegotiating its contract.
Asked about the delays, Taylor only addressed the situation in Europe — where she said EU shipments have to undergo local testing in the Netherlands before being distributed to local countries — but didn’t address delays elsewhere. She also reiterated the company will have the capacity to produce 2 billion doses annually, a goal Novavax has been promising since 2020. As recently as last April, they said they would reach the capacity by Q3 2021.
Taylor, though, declined to say how many doses the company is producing at the moment — only that they would meet their promises.
“We have commitments in place for 2 billion doses,” she said. “That is a good match, we can make as much as we need to supply our dose commitments.”