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.
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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.
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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.
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The research paper
Efficacy of NVX-CoV2373 Covid-19 Vaccine against the B.1.351 Variant
https://www.nejm.org/doi/full/10.1056/NEJMoa2103055
Of 6324 participants who underwent screening, 4387 received at least one injection of vaccine or placebo.
Approximately 30% of the participants were seropositive for SARS-CoV-2 at baseline.
Among 2684 baseline seronegative participants (94% HIV-negative and 6% HIV-positive), predominantly mild-to-moderate Covid-19 developed in 15 participants in the vaccine group and in 29 in the placebo group (vaccine efficacy, 49.4%; 95% confidence interval [CI], 6.1 to 72.8).
Vaccine efficacy among HIV-negative participants was 60.1% (95% CI, 19.9 to 80.1).
Of 41 sequenced isolates, 38 (92.7%) were the B.1.351 variant.
Post hoc vaccine efficacy against B.1.351 was 51.0% (95% CI, −0.6 to 76.2) among the HIV-negative participants.
Preliminary local and systemic reactogenicity events were more common in the vaccine group; serious adverse events were rare in both groups.
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In this placebo-controlled vaccine trial, we found that previous infection with first-wave prototype-like, pre-B.1.351 viruses did not appear to reduce the risk of Covid-19 due to subsequent infection with B.1.351 variants among placebo recipients during the initial 2 months of follow-up. This finding is preliminary and may have public health implications for pandemic modeling, control strategies, and vaccine development and deployment efforts.