Novavax Covid Vaccine Is Highly Effective Against U.K. Variant But Struggled In South Africa, Data Shows

Published 3 years ago
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TOPLINE A Covid-19 vaccine candidate from Novavax offers strong protection against a more contagious coronavirus variant first discovered in the United Kingdom, but it’s somewhat less effective against a rapidly spreading mutation from South Africa, according to early data released Thursday, marking the latest vaccine to face some efficacy issues as new strains of the virus evolve.


Novavax’s vaccine, which hasn’t been approved for use yet, was 89.3% effective in the United Kingdom, according to data from a phase 3 trial in that country (it was 86% effective against the new U.K. variant and 96% effective for other forms of the virus).

In a smaller study in South Africa, a country dominated by a highly contagious new coronavirus variant, the vaccine was just 49.4% effective, though its efficacy jumped by more than 10 points for patients who are HIV-negative.


Following the announcement, Novavax’s share price rose 29.2% in after-hours trading to $173.11.


Novavax says it’s working on a new version of the vaccine that could offer stronger immunity against the South Africa variant, and it hopes to launch trials in the second quarter of this year. Still, in a conference call Thursday, executives cast the South Africa results as proof its vaccine offers some protection against an increasingly common strain of the virus.


In recent months, more contagious new coronavirus strains have torn through the United Kingdom, Brazil and South Africa and quickly spread to dozens of other countries including the United States. Some experts are concerned existing vaccines could offer less protection against new forms of the virus. Novavax isn’t the only vaccine developer to watch these new variants closely: Moderna and Pfizer say their vaccines (which are currently being distributed in the United States) appear to be slightly less effective in South Africa than in the United Kingdom, leading Moderna to start developing a booster to improve immunity against the South Africa variant.


Seasonal flu vaccines often have efficacy rates below 50%, according to data from the Centers for Disease Control and Prevention.



Novavax says it plans on starting the approval process with regulators soon. The Gaithersburg, Md.-based biotech company, which specializes in vaccines, will likely ask for authorization in the United Kingdom first, executives said, and it has begun speaking with regulators in the United States, where a phase 3 trial kicked off last year and is expected to wrap up in March. Novavax has agreed to produce 100 million doses for U.S. patients, part of a deal struck through Operation Warp Speed last year.


“We look forward to continuing to work with our partners, collaborators, investigators and regulators around the world to make the vaccine available as quickly as possible,” Novavax CEO Stanley Erck said in a statement Thursday.