Influenza vaccines are given each year to protect against specific strains circulating in humans predicted to be the most prevalent during flu season. These vaccines are a critical public health tool to fight seasonal influenza but are unlikely to provide protection against viruses emerging from animals with pandemic potential. Researchers funded by the National Institute of Allergy and Infectious Diseases (NIAID) Centers of Excellence for Influenza Research and Response (CEIRR) and Collaborative Influenza Vaccine Innovation Centers (CIVICs) developed an experimental multivalent influenza vaccine that extends immune responses beyond the narrow protection that seasonal vaccines provide.
The study led by Dr. Scott Hensley's lab at the University of Pennsylvania, and in collaboration with Dr. Seema Lakdawala’s lab, both part of Penn-CEIRR, assessed the efficacy of an mRNA-based vaccine targeting the viral surface glycoprotein hemagglutinin. The authors built upon recent advances in mRNA technology used in current COVID-19 vaccines to deliver more antigens at once than what is feasible through other approaches. Twenty unique mRNAs encoding hemagglutinins from the 18 known influenza A subtypes and two influenza B lineages were encapsulated in a lipid nanoparticle system and administered to mice and ferrets. The multivalent mRNA vaccine was highly effective at stimulating cross-reactive and subtype-specific antibodies in both mice and ferrets and protected animals from severe illness following infection with strains both like and unlike those used to produce the vaccine.
By incorporating 20 diverse antigens into a single vaccine, investigators elicited broad protection absent of the viral mismatch limitations currently hindering seasonal flu vaccines. This work advances development of a “universal” influenza vaccine to defend against seasonal and pandemic flu. To read more about this study, check out the NIH Director’s Blog and Penn Medicine News. To read the full article, click here.