Novavax COVID-19 vaccine is 89 percent effective, but much less so against South African strain

Novavax, a biotech firm based in Maryland, announced Thursday that its COVID-19 vaccine was 89.3 percent effective at protecting people from the disease in Britain, including against a new and more infectious strain now dominant in the U.K., but only 49 percent effective in a smaller trial in South Africa. More than 90 percent of the South African subjects who got sick were infected with the new strain, according to preliminary results. Novavax announced the interim results of its Phase 3 U.K. study and Phase 2 trial in South Africa in a press release.

Novavax's findings were a sobering signal that the current vaccines won't work as well against the new variants. The company's vaccine appeared to be 95.6 percent effective against the original strain of the coronavirus but 85.6 percent effective against the U.K. variant. Novavax also said its vaccine was 60 percent effective in its South African trial if you excluded the subgroup with HIV. It is already working on a modified version of its vaccine to specifically target the South African variant, which was first confirmed have hit the U.S. on Thursday.

The U.S. has approved COVID-19 vaccines from Pfizer/BioNTech and Moderna, and Johnson & Johnson is expected to release the findings of its Phase 3 trial sometime next week. Johnson & Johnson has been testing its vaccine in South Africa and Brazil, home to another new mutation, so health experts are hoping to get more clues about how current vaccines fare against the new strains.

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Novavax said it has already started the process to seek regulatory approval for its vaccine in the U.K., and it could be approved in the U.S. as early as April, though the Food and Drug Administration might wait for the results of its ongoing Phase 3 trial in Mexico and the U.S. Public health officials would welcome any new supply of a safe and effective vaccine. The FDA has said vaccine candidates have to be at least 50 percent effective. The U.S. contributed $1.6 billion to Novavax's vaccine effort last year and has preordered 100 million doses.