Novavax COVID-19 vaccine 55 percent effective against South African variant

In an initial primary analysis of the Phase 2b trial of COVID-19 vaccine NVX-CoV-2373, a New England Journal of Medicine-published report revealed that the vaccine provided approximately 55 percent efficacy to non-HIV patients when pitted against the South African variant, B.1.351.

The Novavax, Inc. created vaccine underwent a randomized, observer-blinded, and placebo-controlled trial against the SARS-CoV-2 variant in South Africa. That trial focused on evaluating the efficacy, safety, and immunogenicity among healthy adults and conducted a smaller study of efficacy among medically stable adults afflicted with human immunodeficiency virus (HIV). With the 55 percent figure logged for the healthy, the study achieved its primary endpoint, although it represented a fall from the 60 percent demonstrated in the initial analysis.

An initial analysis had been conducted in January, but this latest data provides a more complete picture of the facts. Since that analysis, the B.1.351 variant has continued to spread and dominate the original strain. Still, most cases in the study remained mild to moderate, with only five cases of severe disease emerging, and all of these in the placebo group.

“This data publication reinforces the encouraging safety profile and cross-protective effect across variants seen in studies of our vaccine to date,” Dr. Gregory Glenn, president of research and development for Novavax, said. “It also demonstrates that ongoing evaluation of COVID-19 vaccine efficacy against SARS-CoV-2 variants is urgently needed to inform vaccine development and use.”

The follow-up is important because it undoes a supposition of the initial analysis that prior infection with the original COVID-19 strain did not protect against subsequent infection by the South Africa variant over the course of 60 days. New data showed that it could actually provide a modest protective effect.