Safety and Efficacy of NVX-CoV2373 Covid-19 Vaccine

N Engl J Med. 2021 Sep 23;385(13):1172-1183. doi: 10.1056/NEJMoa2107659. Epub 2021 Jun 30.

Abstract

Background: Early clinical data from studies of the NVX-CoV2373 vaccine (Novavax), a recombinant nanoparticle vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that contains the full-length spike glycoprotein of the prototype strain plus Matrix-M adjuvant, showed that the vaccine was safe and associated with a robust immune response in healthy adult participants. Additional data were needed regarding the efficacy, immunogenicity, and safety of this vaccine in a larger population.

Methods: In this phase 3, randomized, observer-blinded, placebo-controlled trial conducted at 33 sites in the United Kingdom, we assigned adults between the ages of 18 and 84 years in a 1:1 ratio to receive two intramuscular 5-μg doses of NVX-CoV2373 or placebo administered 21 days apart. The primary efficacy end point was virologically confirmed mild, moderate, or severe SARS-CoV-2 infection with an onset at least 7 days after the second injection in participants who were serologically negative at baseline.

Results: A total of 15,187 participants underwent randomization, and 14,039 were included in the per-protocol efficacy population. Of the participants, 27.9% were 65 years of age or older, and 44.6% had coexisting illnesses. Infections were reported in 10 participants in the vaccine group and in 96 in the placebo group, with a symptom onset of at least 7 days after the second injection, for a vaccine efficacy of 89.7% (95% confidence interval [CI], 80.2 to 94.6). No hospitalizations or deaths were reported among the 10 cases in the vaccine group. Five cases of severe infection were reported, all of which were in the placebo group. A post hoc analysis showed an efficacy of 86.3% (95% CI, 71.3 to 93.5) against the B.1.1.7 (or alpha) variant and 96.4% (95% CI, 73.8 to 99.5) against non-B.1.1.7 variants. Reactogenicity was generally mild and transient. The incidence of serious adverse events was low and similar in the two groups.

Conclusions: A two-dose regimen of the NVX-CoV2373 vaccine administered to adult participants conferred 89.7% protection against SARS-CoV-2 infection and showed high efficacy against the B.1.1.7 variant. (Funded by Novavax; EudraCT number, 2020-004123-16.).

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • COVID-19 / epidemiology
  • COVID-19 / prevention & control*
  • COVID-19 Vaccines* / administration & dosage
  • COVID-19 Vaccines* / adverse effects
  • COVID-19 Vaccines* / immunology
  • Humans
  • Immunogenicity, Vaccine*
  • Injections, Intramuscular / adverse effects
  • Middle Aged
  • SARS-CoV-2
  • Single-Blind Method
  • Vaccines, Synthetic / immunology
  • Young Adult

Substances

  • COVID-19 Vaccines
  • Vaccines, Synthetic
  • recombinant SARS-CoV-2 vaccine NVX-cov2373

Supplementary concepts

  • SARS-CoV-2 variants

Associated data

  • EudraCT/2020-004123-16