Novavax COVID-19 vaccine found to be 96.4% effective in final analysis of UK Phase-3 study

US-biotech firm Novavax said on March 12 that its COVID-19 vaccine was 96.4 percent effective against mild, moderate and severe symptoms of the disease in the final analysis of a late-stage trial in the UK.

The analysis showed the vaccine had 86.3 percent efficacy against the UK variant B.1.1.7/501Y.V1 but it dropped to 55.4 percent against the South African variant B1.351 among the HIV-negative trial participants, the company said.

Across both trials in the UK and South Africa, Novavax vaccine demonstrated 100 percent protection against severe disease, including all hospitalisation and death.

The Phase-3 study in the UK enrolled more than 15,000 participants between 18-84 years of age, including 27 percent over the age of 65. The primary endpoint of the Phase 3 clinical trial is based on the first occurrence of symptomatic COVID-19.

The efficacy analysis was based on 106 COVID-19 positive cases observed in the trial. Only 10 positive cases were in the vaccine group and 96 in the placebo group.

"Both studies achieved their statistical success criteria. Today’s final analyses build on the successful interim results announced in January 2021, adding substantially more COVID-19 cases and statistical power," Novavax said.

In both the UK and South Africa trials, the analyses showed that the vaccine is well-tolerated, with low levels of severe, serious (SAEs) and medically attended adverse events at Day 35, balanced between vaccine and placebo groups.

“We are very encouraged by the data showing that NVX-CoV2373 not only provided complete protection against the most severe forms of disease but also dramatically reduced mild and moderate disease across both trials. Importantly, both studies confirmed efficacy against the variant strains,” said Stanley C Erck, President and Chief Executive Officer, Novavax.

Erck indicated they would seek emergency use authorisation for the vaccine.

Novavax vaccine is based on protein sub-unit platform that uses part of the virus and combines with adjuvant, or booster.

On December 28, Novavax initiated a second Phase 3 trial with sites in the US and Mexico and plans to recruit up to 30,000 volunteers. The vaccine's storage temperature requirement is 2-8 degrees Celsius.