(HealthDay News) — A two-dose regimen of the NVX-CoV2373 (Novavax) recombinant nanoparticle vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has efficacy of 89.7% in adults, according to a study published online June 30 in the New England Journal of Medicine.
Paul T. Heath, M.B.B.S., from the University of London, and colleagues conducted a phase 3, randomized trial at 33 U.K. sites involving adults aged 18 to 84 years. A total of 15,187 participants were randomly assigned to receive two intramuscular 5-µg doses of NVX-CoV2373 or placebo, 21 days apart, in a 1:1 ratio. The per-protocol efficacy population included 14,039 participants.
The researchers found that infections were reported in 10 and 96 participants in the vaccine and placebo groups, respectively, with a symptom onset of at least seven days after the second dose; vaccine efficacy in this per-protocol efficacy population was 89.7%. Among the 10 breakthrough cases in the vaccine group, there were no hospitalizations or deaths. There were five cases of severe infection, all in the placebo group. In a post-hoc analysis, vaccine efficacy was 86.3 and 96.4% against the B.1.1.7 (alpha) variant and against non-B.1.1.7 variants, respectively. Reactogenicity was generally found to be mild and transient. Serious adverse event incidence was low and similar in the two groups.
“A two-dose regimen of the NVX-CoV2373 vaccine administered to adult participants conferred 89.7 percent protection against SARS-CoV-2 infection and showed high efficacy against the B.1.1.7 variant,” the authors write.
Several authors disclosed financial ties to Novavax, which manufactures the NVX-CoV2373 vaccine and funded the study.
