Novavax vaccine almost 90 percent effective in trial, but not against South Africa variant

Novavax’s COVID-19 vaccine has been found to be almost 90 percent effective in a clinical trial in the United Kingdom, the company said Thursday, but was far less effective in a separate trial in South Africa given the variant prevalent there.

Efficacy was strong in the UK trial, at 89.3 percent, the company said.

But in a separate, smaller trial in South Africa, where a more contagious variant of the virus known as  B.1.351.has taken hold, efficacy fell sharply to 49.4 percent, though it was somewhat higher, at 60 percent, among participants who did not have HIV.

That news is problematic for the U.S.,where the more contagious variant was found in South Carolina just hours before the announcement. Even more problematic, the U.S. is so far behind much of the world in genetic sequencing, we don’t know how widespread this new variant is.

The South Africa trial had just 4,400 volunteers, but the results were enough for the company to say it will be working on a booster specifically for that variant.