Novavax COVID-19 Vaccine Demonstrates 90% Overall Efficacy, 100% Protection Against Moderate and Severe Disease

The recombinant nanoparticle protein-based COVID-19 vaccine NVX-CoV2373 (Novavax) was found to provide 100% protection against moderate and severe disease and 90.4% efficacy overall in the phase 3 PREVENT-19 trial.

During the trial, investigators enrolled 29,960 people in the United States and Mexico to assess the efficacy, safety, and immunogenicity of the vaccine. Taking place across 119 sites, the study focused on including a population representative of the communities and demographic groups that have been shown to be most affected by the disease.

"Today, Novavax is one step closer to addressing the critical and persistent global public health need for additional COVID-19 vaccines. These clinical results reinforce that NVX-CoV2373 is extremely effective and offers complete protection against both moderate and severe COVID-19 infection," said Stanley C. Erck, president and chief executive officer, Novavax, in a press release. "Novavax continues to work with a sense of urgency to complete our regulatory submissions and deliver this vaccine, built on a well understood and proven platform, to a world that is still in great need of vaccines."

The PREVENT-19 trial was a placebo-controlled, observer-blinded study, which was randomized 2:1. Data from the trial demonstrated that NVX-CoV2373 met its primary endpoint with an overall efficacy of 90.4% (95% CI: 82.9, 94.6).

During the trial, 77 cases of COVID-19 were observed, with 63 in the placebo group and 14 in the vaccine group. The observed cases in the vaccine group were mild and in the placebo group there were 10 moderate cases and 4 severe cases observed, yielding a vaccine efficacy of 100% (95% CI: 87, 100) against moderate or severe disease.

Upon the completion of the final phases of process qualification and assay validation, Novavax will file for regulatory authorizations, which is currently planned to occur in the third quarter. Once it receives the necessary regulatory approvals, Novavax plans to manufacture 100 million doses per month by the end of the third quarter of 2021, with plans to increase production to 150 million doses per month by the end of the fourth quarter in order to meet demand.

Data contributing to the efficacy endpoints were obtained between January 25 and April 30, 2021, a time during which the B.1.1.7 Alpha variant, first identified in the United Kingdom, became the predominant strain in the United States. During the PREVENT-19 endpoint accrual window, additional strains also increased, which were referred to as variants of interest (VoI) and variants of concern (VoC).

The sequence data available for 54 out of the 77 COVID-19 cases observed during the PREVENT-19 trial showed that it met its key secondary endpoint as well, demonstrating 100% efficacy (95% CI: 80.8, 100) against variants not considered VoC and VoI.

Among the cases assessed, 65% were VoC, 17% were VoI, and 19% were other variants. Specifically, vaccine efficacy was found to be 93.2% (95% CI: 83.9, 97.1) against VoC and VoI, which represented 82% of the cases, achieving a key exploratory endpoint of the study. Additionally, 38 of the VoC/VoI cases were in the placebo group, whereas 6 occurred in the vaccine group.

Among high-risk populations—which include individuals over 65 years of age and individuals under age 65 years of age who have certain comorbidities or have life circumstances that lead them to have frequent COVID-19 exposure—NVX-CoV2373 was found to have an efficacy of 91.0% (95% CI: 83.6, 95.0), with 62 of the COVID-19 cases occurring in the placebo group and 13 occurring in the vaccine group.

"PREVENT-19 confirms that NVX-CoV2373 offers a reassuring tolerability and safety profile," said Gregory M. Glenn, MD, president of research and development, Novavax, in the press release. "These data show consistent, high levels of efficacy and reaffirm the ability of the vaccine to prevent COVID-19 amid ongoing genetic evolution of the virus. Our vaccine will be a critical part of the solution to COVID-19 and we are grateful to the study participants and trial staff who made this study possible, as well as our supporters, including the US government."