Even with increased global surveillance, it is difficult to predict which flu strain will cause the next flu pandemic. Therein lies the importance of creating a universal vaccine.
A new multivalent mRNA vaccine candidate marks another step towards a universal flu vaccine.
Claudia Arevalo, of the University of Pennsylvania in the US city of Philadelphia, and colleagues have developed an mRNA lipid nanoparticle vaccine that contains antigens from all 20 known subtypes of influenza A and B viruses, a strategy that can serve as the basis for the universal flu vaccines.
Their vaccine produced high levels of subtype-specific and cross-reactive antibodies in mice and ferrets and was able to protect the animals from disease symptoms and death after infection with antigenically matched and unmatched influenza strains. .
The approach by Arevalo and his colleagues differs from previous attempts to develop a universal flu vaccine by including specific antigens for each subtype, rather than just a smaller set of antigens shared across subtypes.
Simplified digital representation of the influenza virus. (Illustration: Dan Higgins/CDC/Douglas Jordan)
Following the success of mRNA vaccines against the SARS-CoV-2 coronavirus, researchers have prepared 20 different mRNAs encapsulated in nanoparticles, each of which encodes a different hemagglutinin antigen, a highly immunogenic influenza protein that helps the virus enter cells.
Antibody levels were essentially stable four months after vaccination in mice.
Multivalent protein vaccines produced using more traditional methods elicited fewer antibodies and were less protective than the multivalent mRNA vaccine in animals.
Arevalo and his colleagues discuss the technical details of their vaccine in the academic journal Science, titled “A Nucleoside-Modified Multivalent mRNA Vaccine Against All Known Influenza Virus Subtypes.” (Source: AAAS)
