NEW YORK & MAINZ, Germany – Pfizer Inc. and BioNTech SE recently announced results from their Phase 3 trial for a combined mRNA-based vaccine targeting both influenza and COVID-19. The combination vaccine, administered to adults aged 18 to 64, demonstrated a mixed outcome in its primary immunogenicity goals. While achieving promising responses against the influenza A strain and comparable COVID-19 immunity, the vaccine fell short of its non-inferiority goal against the influenza B strain. The companies are now exploring adjustments to enhance immune responses against influenza B and plan to discuss further steps with health authorities.
Phase 3 Trial Insights: Safety and Immunogenicity
The randomized, observer-blinded trial involved over 8,000 participants who received the combination vaccine, comparing it to standard licensed influenza and COVID-19 vaccines. Results indicated that the combination vaccine generated strong immune responses against influenza A, surpassing those of a traditional influenza vaccine, and matched responses to SARS-CoV-2 seen with a licensed COVID-19 vaccine. Despite these successes, the response to influenza B was lower, marking a setback in the trial’s immunogenicity objective.
The safety profile of the combination vaccine was consistent with previous mRNA vaccine trials, showing no new safety concerns in the ongoing review. Participants receiving separate licensed influenza and COVID-19 vaccines continued to display strong immune responses to both viruses without adverse safety signals.
“We are encouraged by the robust immunogenicity we saw with our combination vaccine against influenza A,” said Annaliesa Anderson, Ph.D., Senior Vice President and Head of Vaccine Research and Development at Pfizer. “We believe combination vaccines are the most efficient way to reduce the burden of respiratory diseases.”
Update on Pfizer’s Standalone Trivalent mRNA Influenza Vaccine
Pfizer also shared updates on its standalone trivalent mRNA influenza vaccine program. In a separate Phase 2 trial, Pfizer tested second-generation trivalent influenza vaccine candidates, aiming to improve efficacy across strains. Preliminary findings from this trial indicated robust immune responses against both influenza A and B strains in individuals aged 18 to 64, supporting the potential of mRNA technology in combating influenza.
Impact of Influenza and the Potential of mRNA Technology
Influenza remains a significant health burden, leading to hundreds of thousands of hospitalisations and tens of thousands of deaths annually in the U.S. Current vaccines, though effective, often offer limited protection, especially in years with poor strain matching. mRNA technology’s adaptability offers hope for more responsive vaccine development, especially for rapidly evolving viruses.
The results of these trials underscore the potential of mRNA technology to address multiple respiratory threats through combination vaccines, enhancing protection and easing logistical demands of administering separate vaccinations.
