Extended durability of protection against infection and disease is shown in United Kingdom COVID-19 vaccine phase III clinical trial.

Additionally, the analysis showed vaccine efficacy of 82.5% (95% CI: 75.0, 87.7) in protection against all COVID-19 infection – both symptomatic and asymptomatic – as measured by PCR+ or anti-N seroconversion.

"These data have two implications for NVX-CoV2373. Importantly, the vaccine offers protection against symptomatic and asymptomatic COVID-19 infection which may both interrupt virus transmission and prevent COVID-19 disease," said Gregory M. Glenn, M.D., President of Research and Development, Novavax. "Additionally, we are encouraged to see that our COVID-19 vaccine maintains a high level of durable efficacy and continues to exhibit a reassuring safety profile in this extended timeframe."

The data build upon the final analysis of the UK Phase III trial, published in the New England Journal of Medicine in June 2021, ( previously cited) which was used as part of Novavax' regulatory submissions for NVX-CoV2373 around the world and demonstrated a vaccine efficacy of 89.7% (95% CI: 80.2, 94.6), with cases collected over three months (median of 55 days of surveillance). In the expanded data collection window, vaccine efficacy was evaluated over a 6-month period from November 10, 2020, through May 10, 2021 (median of 101 days of surveillance). NVX-CoV2373 continued to show a reassuring safety profile during this window, with adverse events that were balanced between vaccine and placebo groups.

Additionally, the trial demonstrated continued protection with an overall vaccine efficacy of 82.7% (95% CI: 73.3, 88.8). Vaccine efficacy against severe disease was 100% (95% CI: 17.9, 100) during the 6-month efficacy collection window, in line with the initial analysis.