Maryland-based biotech company Novavax said that its COVID-19 vaccine is 90.4% effective in a late-stage trial of nearly 30,000 people in the U.S. and Mexico, possibly offering the United States another weapon against the deadly virus.

What You Need To Know

  • Novavax said that its COVID-19 vaccine is 90.4% effective in a late-stage trial of nearly 30,000 people in the U.S. and Mexico, and is effective against some variants

  • The study enrolled nearly 29,960 adults in the U.S. and Mexico; there were 77 confirmed COVID-19 cases in the study, 63 were seen in the placebo group, compared to 14 in the vaccine group

  • The company's president of research and development that these results are similar to what they saw in a Phase 3 clinical trial in the U.K.

  • The company plans to file for Emergency Use Authorization with the Food and Drug Administration in the third quarter of 2021

The two-dose vaccine was also 100% effective at preventing moderate and severe cases of COVID-19 and 93% effective against some variants, the company said.

"Today, Novavax is one step closer to addressing the critical and persistent global public health need for additional COVID-19 vaccines," Stanley Erck, the company's president and CEO, said in a statement. "These clinical results reinforce that NVX-CoV2373 is extremely effective and offers complete protection against both moderate and severe COVID-19 infection."

The study enrolled nearly 29,960 adults across 113 sites in the U.S. and 6 in Mexico. There were 77 confirmed COVID-19 cases in the study; 63 were seen in the placebo group, compared to 14 in the vaccine group. All of the vaccinated cases were mild, but 10 moderate cases and four severe cases were seen in the placebo group.

The vaccine was similarly effective against several variants including the one first detected in the United Kingdom, which is dominant in the United States. It was also effective among "high-risk" populations, including the people over 65 and individuals with underlying health problems.

Novavax says the vaccine was "generally well-tolerated," with low numbers of severe side-effects. The most common symptoms experienced were injection site pain and tenderness, which lasted less than three days; headache and muscle pain were also common and lasted less than two days.

"PREVENT-19 confirms that NVX-CoV2373 offers a reassuring tolerability and safety profile," Gregory M. Glenn, M.D., the company's president of research and development, said. "These data show consistent, high levels of efficacy and reaffirm the ability of the vaccine to prevent COVID-19 amid ongoing genetic evolution of the virus. Our vaccine will be a critical part of the solution to COVID-19 and we are grateful to the study participants and trial staff who made this study possible, as well as our supporters, including the U.S. Government."

Dr. Glenn told CNN that these results are similar to what they saw in a Phase 3 clinical trial in the U.K.

"Different continent, different population, different viruses floating around, and yet, we still see really good efficacy," he said. "This is what you want to have."

The company plans to file for Emergency Use Authorization with the Food and Drug Administration in the third quarter of 2021. Upon approval, Novavax says, they are "on track" to reach manufacturing capacity to produce 100 million doses per month by the end of the third quarter, and 150 million doses per month by the end of the fourth quarter.

The study will be submitted to peer-review journals for publication, the company said, as they continue to analyze the results of the trial.

COVID-19 vaccines train the body to recognize the coronavirus, especially the spike protein that coats it, and get ready to fight the virus off. The Novavax vaccine is made with lab-grown copies of that protein. That’s different from some of the other vaccines now widely used, which include genetic instructions for the body to make its own spike protein.

Novavax's vaccine can be stored in standard refrigerators, making it easier to distribute.

The Associated Press contributed to this report.