Novavax vaccine 89% effective in UK trial, less effective in South Africa
Novavax said its protein-based COVID-19 vaccine candidate, NVX-CoV2373, was nearly 90% efficacious in a phase 3 clinical trial in the United Kingdom, during which most cases were attributed to the emerging B.1.1.7 variant.
Results of a phase 2b study in South Africa showed it was 60% efficacious (95% CI, 19.9%-80.1%) at preventing mild, moderate and severe cases among HIV-negative participants in that country, and 49% efficacious (95% CI, 6.1%-72.8%) when both HIV-positive and HIV-negative participants were included.
According to Novavax, more than 90% of cases during the South African trial were attributable to the B.1.351 variant, which has raised concerns over its ability to evade vaccines and therapies and was just reported in the United States for the first time.
The U.K. trial enrolled more than 15,000 participants aged 18 to 84 years, with 27% being aged older than 65 years. An initial interim analysis showed there were 62 cases, of which 56 occurred in the placebo group and six in the vaccine group, for an efficacy of 89.3% (95% CI, 75.2%-95.4%).
Based on PCR-tested strains from 56 of the 62 cases, the reported efficacy by strain was 95.6% against the original COVID-19 strain and 85.6% against the B.1.1.7 variant.
“These are spectacular results, and we are very pleased to have helped Novavax with the development of this vaccine,” U.K. Vaccine Taskforce chair Clive Dix, PhD, said in a statement. “The efficacy shown against the emerging variants is also extremely encouraging. This is an incredible achievement that will ensure we can protect individuals in the U.K. and the rest of the world from this virus.”
In the phase 2b trial in South Africa, 29 cases were observed in the placebo group, and 15 cases were observed in the vaccine group.
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I think the data were generally encouraging. I mean, it was 90% effective at preventing mild, moderate and severe disease in the U.K. It was less effective at preventing mild, moderate to severe disease in South Africa, where the South African strain is common.
What would be interesting to know is to what extent it protected against severe disease. Or said another way, hospitalizations and death in South Africa — you'd like to know that. Unfortunately, the study was relatively small; it included only about 4,000 people. But that's what you really want to know.
This is the problem with living in an age of science by press release — you don't really get to know those data because you're not looking at all the data, you’re just looking at what the press release is telling you.
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Novavax. Novavax COVID-19 vaccine demonstrates 89.3% efficacy in UK phase 3 trial. https://ir.novavax.com/news-releases/news-release-details/novavax-covid-19-vaccine-demonstrates-893-efficacy-uk-phase-3. Accessed January 29, 2021.
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