A new approach could serve as the basis for a universal flu vaccine

Claudia Arevalo and colleagues have developed an mRNA lipid nanoparticle vaccine containing antigens from all 20 known subtypes of influenza A and B viruses, a strategy that could serve as the basis for a universal influenza vaccine.

Their vaccine produced high levels of cross-reactive and subspecies-specific antibodies in mice and ferrets and could protect animals from disease symptoms and death after infection with both antigenically matched and mismatched strains of influenza. Even with increased global surveillance, it is difficult to predict which flu strain will cause the next flu outbreak, making a universal vaccine important.

Arevalo’s approach and more. differs from previous attempts to create a universal influenza vaccine by containing antigens specific to each subtype, rather than a slightly smaller set of antigens shared between subtypes. Following the success of mRNA vaccines against SARS-CoV-2, the researchers prepared 20 different nanoparticle-encapsulated mRNAs, each encoding a different hemagglutinin antigen – a highly immunogenic influenza protein that helps the virus enter cells. Antibody levels remained largely constant four months after vaccination in the mice. Polyvalent protein vaccines produced by more conventional methods elicited fewer antibodies and were less protective compared to the polyvalent mRNA vaccine in animals.

In a related perspective, Alyson Kelvin and Darryl Falzarano discuss the findings, noting that “questions remain about the regulatory and approval process for such a vaccine that targets pandemic viruses but is not currently circulating in humans.”

Source:

American Association for the Advancement of Science (AAAS)

Diary reference:

Arevalo, CP, and more. (2022) A polyvalent nucleoside-modified mRNA vaccine against all known influenza virus subtypes. Science. doi.org/10.1126/science.abm0271.

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