Researchers test mRNA technology for universal flu vaccine

CureVac NV

24/11/2022 19:00

By Nancy Lapid
       Nov 24 (Reuters) - An experimental vaccine provided
broad protection against all 20 known influenza A and B virus
subtypes in initial tests in mice and ferrets, potentially
opening a pathway to a universal flu shot that might help
prevent future pandemics, according to a U.S. study published on
Thursday.
    The two-dose vaccine employs the same messenger RNA
(mRNA)technology used in the COVID-19 shots developed by Pfizer
 PFE.N  with BioNTech  22UAy.DE , and by Moderna  MRNA.O . It
delivers tiny lipid particles containing mRNA instructions for
cells to create replicas of so-called hemagglutinin proteins
that appear on influenza virus surfaces.
    A universal vaccine would not mean an end to flu seasons,
but would replace the guess work that goes into developing
annual shots months ahead of flu season each year.
    "The idea here is to have a vaccine that will give people a
baseline level of immune memory to diverse flu strains, so that
there will be far less disease and death when the next flu
pandemic occurs," study leader Scott Hensley of the Perelman
School of Medicine at the University of Pennsylvania said in a
statement.
    Unlike standard flu vaccines that deliver one or two
versions of hemagglutinin, the experimental vaccine includes 20
different types in the hope of getting the immune system to
recognize any flu virus it might encounter in the future.
    In lab experiments, vaccinated animals' immune systems
recognized the hemagglutinin proteins and defended against 18
different strains of influenza A and two strains of influenza B.
Antibody levels induced by the vaccine remained unchanged for at
least four months, according to a report published in the
journal Science. 
    The vaccine reduced signs of illness and protected from
death even when the ferrets were exposed to a different type of
flu not in the vaccine, the researchers said.
    Moderna and Pfizer both have mRNA flu vaccines in late-stage
human trials, and GSK  GSK.L  and partner CureVac  5CV.DE  are
testing an mRNA flu vaccine in an early-stage safety trial in
humans. These vaccines are designed to defend against only four
recently-circulating influenza strains but could theoretically
be changed up each year.
    The universal flu vaccine, if successful in human trials,
would not necessarily prevent infection. The goal is to provide
durable protection against severe disease and death, Hensley
said.
    Questions remain regarding how to judge efficacy and
potential regulatory requirements for a vaccine against possible
future viruses that are not currently circulating, Alyson Kelvin
and Darryl Falzarano of the University of Saskatchewan, Canada,
wrote in a commentary published with the study.
    While the promising results with the new vaccine "suggest a
protective capacity against all subtypes of influenza viruses,
we cannot be sure until clinical trials in volunteers are done,"
Adolfo García-Sastrem, director of the Institute for Global
Health and Emerging Pathogens at Mount Sinai Hospital in New
York, said in a statement. 
 (Reporting by Nancy Lapid; Editing by Christine Soares and Bill
Berkrot)
 ((Nancy.Lapid@thomsonreuters.com;))