Novavax, a small American company that has benefited from generous support from the US government, announced the results of a clinical trial of its Covid-19 vaccine in the United States and Mexico on Monday, noting that its two-shot Vaccination offers effective protection against the coronavirus.
In the 29,960-person study, the vaccine showed an overall effectiveness of 90.4 percent, on par with the vaccines from Pfizer-BioNTech and Moderna and higher than the single-use vaccine from Johnson & Johnson. The Novavax vaccine was shown to be 100 percent effective in preventing moderate or severe illness.
Despite these impressive results, the future of the vaccine in the United States remains uncertain and may be needed more in other countries. Novavax says it won't be able to apply for an emergency permit from the Food and Drug Administration until the end of September. And with an ample supply of three other approved vaccines, the agency may instruct Novavax to apply for a full license instead – a process that could take several additional months.
The company's chief executive, Stanley Erck, admitted in an interview that Novavax would likely get its first approval elsewhere. The company is also applying in the UK, the European Union, India and South Korea.
"I think the good news is that the data is so compelling that it gives anyone an incentive to pay attention to our records," said Mr. Erck.
If Novavax gets the green light from the US government, it could be too late to contribute to the country's first wave of vaccinations. However, many vaccine experts expect the country will eventually need booster vaccinations as immunity declines and variants emerge. And the protein-based technology used in the Novavax vaccine can do a particularly good job of enhancing protection, even if people have previously been vaccinated with a different formulation.
"They really might be the right ones for boosters," said Dr. Luciana Borio, the acting chief scientist of the F.D.A. from 2015 to 2017.
Last year, the Trump administration's Operation Warp Speed program awarded Novavax a $ 1.6 billion contract for 100 million future cans. The company gained this tremendous support despite not having launched a vaccine in over three decades.
In January, Novavax announced that its 15,000-person study in the UK found the vaccine to be 96 percent effective against the original coronavirus. Against Alpha, a virus variant identified for the first time in Great Britain, the effectiveness fell slightly to 86 percent. In South Africa, where Novavax conducted a smaller study of 2,900 people and dominated the beta variant, the company found an effectiveness of only 49 percent.
But the South Africa study was made difficult by the fact that a number of the H.I.V. known to interfere with vaccines. In addition, the study was so small that it was difficult to estimate how much protection the vaccine provided to H.I.V. negative volunteers.
With the support of Operation Warp Speed, Novavax made plans for an even larger late-stage trial in the United States and Mexico. But manufacturing difficulties delayed the launch until December.
By then, the United States had approved the Pfizer-BioNTech and Moderna vaccines. In February, while the Novavax trial was ongoing, the Johnson & Johnson’s government approved.
While Novavax waited for the study results, Novavax has teamed up with other companies to begin manufacturing massive quantities of its vaccine. In India it has partnered with the Serum Institute and in South Korea with SK Biosciences. Novavax has reached an agreement with Gavi, the Vaccine Alliance, to supply 1.1 billion doses to middle and low income countries.
The company's scaling difficulties persisted, however, and it took more time to develop specific tests to validate the quality of its product.
The new results were based on 77 test subjects who contracted Covid-19. The volunteers who received the placebo shots got sick much more often than the vaccinated, a statistical difference that resulted in an effectiveness of 90.4 percent.
"That's a strong result," said Natalie Dean, biostatistician at the University of Florida. "It takes you to this high level."
The vaccine showed the same effectiveness in a group of high-risk volunteers – people who were over 65 years old, had medical risk factors, or had jobs that exposed them to the virus.
Novavax sequenced the genomes of 54 of the 77 virus samples and found that half were alpha, the variant that became predominant in the United States that spring.
The side effects of the vaccine were relatively mild. Some volunteers reported fatigue, headaches, and other minor symptoms. "This vaccine seems to make the arms lighter," said John Moore, a virologist at Weill Cornell Medicine who volunteered in the Novavax study.
Novavax will file for approval in the United States after it completes the development of a quality control test, the managing director said. “You definitely have to test them from Sunday to show that you get the same answer under all conditions,” said Erck. "And that takes time."
Mr. Erck said the company plans to produce 100 million cans per month by the end of the third quarter and 150 million cans per month by the end of the fourth quarter.
Every week the United States is building up a wider range of approved vaccines from other companies, raising the question of whether the country needs to issue more emergency approvals or EUAs.
"The law says that once you have adequate doses, no additional E.U.A. is required," said Dr. Borio.
A sign that the F.D.A. changes its approach to Covid-19 vaccines, came last week. An American company called Ocugen had applied for an emergency permit for Covaxin, a Covid-19 vaccine that is now used in India. But on Thursday the company announced that the F.D.A. had recommended instead to choose the standard route to full approval, the so-called biologics license application, which takes many additional months.
But because Novavax is working with the F.D.A. Speaking of his studies last year, Mr. Erck said the company may be able to continue with its emergency permit application plans.
"So far you have indicated that if you are for an EU, you can move on for an EU," said Mr Erck. "Anyone could tell you that could change, but I don't know how to predict it."
Dr. Paul Offit, a professor at the University of Pennsylvania and a member of the F.D.A.'s Vaccine Advisory Board, said Novavax's highly potent vaccine was very welcome. "The more the better," he said. "I think there is still room for many more vaccines because we will be dealing with this virus for years, if not decades."
Novavax is preparing for this future by researching how its vaccine could work as a booster. A new version of the vaccine contains the beta variant proteins that were first identified in South Africa.
Researchers gave baboons beta boosters that had been vaccinated a year ago in experiments with the original version of the Novavax vaccine. The researchers found that the baboon's immunity to Covid-19 skyrocketed after this booster, protecting them from beta, alpha, and the original version of the coronavirus.
"When you boost, you see a very high recall response," said Matthew Frieman, a virologist at the University of Maryland School of Medicine and co-author of the new study. The study has not yet been published in a scientific journal.
Dr. Frieman said the new study offers encouraging evidence that Novavax vaccines might work well as boosters. It also suggested that first time vaccines people might do well to get a mix of the original and beta versions to expand their protection against new variants, he said.
"Novavax can be used as a booster in the US, but it will certainly be the first vaccine many people around the world see," he said