Novavax vaccine highly effective in UK trial, but drops against South Africa variant

Novavax said Thursday that final data from a trial in the United Kingdom shows its COVID-19 vaccine is almost 90 percent effective, but the vaccine was far less effective in a separate trial in South Africa, given the virus variant there that has raised concerns about weakening vaccines.

The data from the U.K. trial was very strong, and similar to interim data released in January. The final data showed the vaccine is 96 percent effective against the original virus strain, and 86 percent effective against the variant identified in the U.K., for overall effectiveness of 89.7 percent.

In South Africa, where a concerning variant is highly prevalent, the effectiveness was far lower, at 48.6 percent, though it was a little higher, at 55 percent, among people who did not have HIV.

Importantly, though, the data released Thursday show that the vaccine still had 100 protection against severe cases, even in the South African study.

Many experts have pointed to strong effectiveness against severe cases across multiple vaccines as among the most important data points, given that keeping people out of the hospital and preventing them from dying is the ultimate goal.

Novavax, a Maryland-based company, said it “expects the data to serve as the basis for submission for authorization to various regulatory agencies worldwide.”

It was not immediately clear if it would apply right away for U.S. authorization, or wait for an ongoing U.S. trial to finish.

“We are very encouraged by the data showing that [the vaccine] not only provided complete protection against the most severe forms of disease, but also dramatically reduced mild and moderate disease across both trials,” Novavax CEO Stanley Erck. “Importantly, both studies confirmed efficacy against the variant strains.”