As part of Novavax's Phase 3 clinical trial of NVX-CoV2373, its recombinant nanoparticle protein-based COVID-19 vaccine candidate, 431 volunteers in the UK took part in a sub-study at St George’s, University of London, and St George’s Hospital.
All received an approved seasonal influenza vaccine (Seqirus, adjuvanted, trivalent seasonal influenza vaccine (aTIV) or a cell-based, quadrivalent seasonal influenza vaccine (QIVc)).
Around half of the participants were also co-vaccinated with NVX-CoV2373 while the remainder received a placebo.
“The study demonstrated that vaccine efficacy appeared to be preserved in those receiving both vaccines compared to those vaccinated with NVX-CoV2373 alone,” notes the company.
Anti-spike antibodies remain higher than convalescent serum
Immunogenicity of the influenza vaccine was preserved; while a ‘modest’ decrease in the immunogenicity of the NVX-CoV2373 vaccine was observed.
Vaccine efficacy of the COVID-19 shot in the sub-study was 87.5% (95% CI: -0.2, 98.4) while efficacy in the main study was 89.8% (95% CI: 79.7, 95.5).
However, despite the decrease in the immunogenicity with concomitant vaccination, anti-spike antibody levels were still more than 3-fold higher than levels found in convalescent serum in those who received both vaccines.
"As the next influenza season approaches and people still need a primary COVID-19 vaccine series or a booster, separate healthcare visits to cover both COVID-19 and influenza vaccinations will be burdensome," said Gregory M. Glenn, M.D., President of Research and Development, Novavax.
"As the first clinical study to evaluate safety, immunogenicity, and efficacy of a COVID-19 vaccine when co-administered with a seasonal influenza vaccine, these results demonstrate the promising opportunity for concomitant vaccination, which may improve the uptake of both vaccines."
Raja Rajaram, M.D., Medical Affairs Lead, EMEA, Seqirus, and a co-author of the study, added: "These data could be used to help inform guidance or recommendations on the co-administration of influenza and COVID-19 vaccines, overcoming challenges and contributing towards a new normal to protect at-risk populations from both infections."
The pre-print study is available online at medRxiv.org.