The American biotech firm made the announcement on Monday based on data from the first co-administration study of a COVID-19 vaccine candidate and an approved influenza vaccine.

Novavax said that as part of its Phase 3 clinical trials of its recombinant nanoparticle protein-based COVID-19 vaccine candidate, all 431 U.K. volunteers received an approved seasonal influenza vaccine. Roughly half the participants were co-vaccinated with the company's COVID-19 vaccine while the remainder received placebo.

Its the first clinical study to evaluate safety, immunogenicity, and efficacy of a COVID-19 vaccine when co-administered with a seasonal influenza vaccine.

"The study demonstrated that vaccine efficacy appeared to be preserved in those receiving both vaccines compared to those vaccinated with NVX-CoV2373 alone," the company said in a statement. Vaccine efficacy was reported at 87.5 percent compared to 89.8 percent in the main study.

"The findings suggest simultaneous vaccination may be a viable immunization strategy," the company added.