Thread by @Novavax

We're thrilled to announce that PREVENT-19 (US/Mex Phase 3) results were submitted for publication. The manuscript is now available as a pre-print. Let's dive into what we found. Thread: medrxiv.org/content/10.110…

PREVENT-19 builds on observations from other/ongoing #clinicaltrials, investigating the safety & efficacy of NVX-CoV2373 in the United States and Mexico amidst an evolving #COVID19 pandemic. ir.novavax.com/2021-08-05-Nov…

The trial randomized adults age 18+ in a 2:1 ratio to receive 2x 5μg doses of NVX-CoV2373, our investigational #vaccine candidate, or placebo, 21 days apart. novavax.com/sites/default/…

PREVENT-19 also included a blinded crossover where those originally randomized to placebo would receive active vaccine & vice versa, ensuring all participants received NVX-CoV2373 without compromising @FDA-required safety follow-up.

Trial sites were selected to prioritize racial and ethnic diversity, as well as those at high risk of acquisition or complications of COVID-19.

The trial’s primary endpoint was the efficacy of NVX-CoV2373 in preventing RT-PCR-confirmed, symptomatic mild, moderate or severe COVID-19 onset ≥7 days after the second vaccine dose.

25,452 participants were included in the efficacy analysis (PP-EFF): 17,312 received NVX-CoV2373 and 8,140 received placebo. The trial included a demographically diverse population.

Results: Solicited adverse events were predominantly mild-to-moderate & transient, but more frequent in the vaccine recipients & increased after the second dose. Severe (Grade 3+) reactions were infrequent.

No safety concerns related to vaccination were seen.

Among per-protocol efficacy participants, there were 77 cases of COVID-19 – 14 in the vaccine group, 63 in the placebo group – for a vaccine efficacy of 90%. All cases in the vaccine group were mild in severity.

Efficacy against moderate-to-severe COVID-19 was 100%, and efficacy against severe disease alone was 100% (post-hoc). Efficacy amongst high-risk populations was 91%.

We saw strong performance against variants. Sequencing was available for 61/77 cases: 13 VoI, 35 VoC and 13 non-VoI/VoC. 31 of the VoC were the alpha (B.1.1.7) strain, demonstrating efficacy of 93.6% (post-hoc).

Efficacy against non-VoI/VoC was 100%. Efficacy against any VoI/VoC was 92.6%. (VoI & VoC definitions from @cdc) cdc.gov/coronavirus/20…

As COVID-19 continues to impact the world, results from PREVENT-19 suggest that NVX-CoV2373 is an important new tool in the global fight against the pandemic.

For a 1-page factsheet on PREVENT-19, visit: novavax.com/sites/default/… (English) and novavax.com/sites/default/… (Espanol) #clinicalresearch

Thank you. Novavax is grateful to the thousands of people around the world who are volunteering for our vaccine studies. We thank the U.S. Government, @CEPIvaccines & other governments for their significant support of our work.