A study published in the New England Journal of Medicine on Wednesday found that the Novavax coronavirus vaccine is 51 percent effective against the South African COVID-19 variant.
The study of the American-made vaccine was conducted in South Africa and included around 2,700 volunteers who had not previously had the coronavirus, Reuters reports.
The study also looked at how effective the vaccine was when compared to people who were HIV positive. Among this demographic, the vaccine was 43 percent effective against the B.1.351 South African strain. The main purpose of the study was to determine how the medicine performed in those who were HIV negative and those who are HIV positive and medically stable.
Ninety-four percent of the participants were HIV negative and six percent were HIV positive.
It was also discovered that prior infection with an earlier version of the coronavirus was not effective at reducing the risk of coronavirus caused by the B.1.351 variant.
The South Africa variant has been shown to be harder to prevent with vaccines available from Pfizer and Moderna. An Israeli study released in April that was not peer-reviewed found that the South Africa variant could “break through” the protection provided by the Pfizer vaccine.
Reuters notes that the vaccine’s efficacy in preventing hospitalization and severe disease was not shown in the published results.
The Novavax vaccine has not been approved for use in the U.S. It is currently under rolling review by the European Medicines Agency (EMA).
In January, Novavax shared that its vaccine had been shown to be 89.3 percent effective at preventing the coronavirus. The phase 3 clinical trial was conducted in the U.K. where over 50 percent of cases are attributable to the more infectious U.K. strain.