Novavax, Inc., a biotechnology company developing next-generation vaccines for serious infectious diseases, announced that NVX-CoV2373, its protein-based COVID-19 vaccine candidate, met the primary endpoint, with a vaccine efficacy of 89.3%, in its Phase 3 clinical trial conducted in the United Kingdom (UK). The study assessed efficacy during a period with high transmission and with a new UK variant strain of the virus emerging and circulating widely. It was conducted in partnership with the UK Government’s Vaccines Taskforce. Novavax also announced successful results of its Phase 2b study conducted in South Africa.

“With today’s results from our UK Phase 3 and South Africa Phase 2b clinical trials, we have now reported data on our COVID-19 vaccine from Phase 1, 2 and 3 trials involving over 20,000 participants. In addition, our PREVENT-19 US and Mexico clinical trial has randomized over 16,000 participants toward our enrollment goal of 30,000. NVX-CoV2373 is the first vaccine to demonstrate not only high clinical efficacy against COVID-19 but also significant clinical efficacy against both the rapidly emerging UK and South Africa variants,” said Stanley C. Erck, President and Chief Executive Officer, Novavax.

NVX-CoV2373 contains a full-length, prefusion spike protein made using Novavax’ recombinant nanoparticle technology and the company’s proprietary saponin-based Matrix-M™ adjuvant. The purified protein is encoded by the genetic sequence of the SARS-CoV-2 spike (S) protein and is produced in insect cells. It can neither cause COVID-19 nor can it replicate, is stable at 2°C to 8°C (refrigerated) and is shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels.