Novavax Offers U.S. a Fourth Strong Covid-19 Vaccine

The company’s large U.S. trial found an efficacy rate of about 90 percent. But at this point, the nation is awash in other shots.

Novavax, a small American company buoyed by lavish support from the U.S. government, announced on Monday the results of a clinical trial of its Covid-19 vaccine in the United States and Mexico, finding that its two-shot inoculation provides potent protection against the coronavirus. In the 29,960-person trial, the vaccine demonstrated an overall efficacy of 90.4 percent, on par with the vaccines made by Pfizer-BioNTech and Moderna, and higher than the one-shot vaccine from Johnson & Johnson. The Novavax vaccine showed an efficacy of 100 percent at preventing moderate or severe disease. Despite these impressive results, the vaccine’s future in the United States is uncertain and it might be needed more in other countries. Novavax says it may not seek emergency authorization from the Food and Drug Administration until the end of September. And with a plentiful supply of three other authorized vaccines, it’s possible that the agency may tell Novavax to apply instead for a full license — a process that could require several extra months.