Researchers test mRNA technology for universal flu vaccine

Nov 24 (Reuters) – An experimental vaccine provided broad protection against all 20 known subtypes of the influenza A and B virus in initial tests in mice and ferrets, potentially opening a path to a universal flu shot that could help future pandemics prevent, according to a US. study published on Thursday.

The two-dose vaccine uses 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 small lipid particles with mRNA instructions for cells to make replicas of so-called hemagglutinin proteins that appear on flu virus surfaces.

A universal vaccine would not mean the end of the flu season, but would replace the guesswork that goes into developing annual vaccinations months before the flu season each year.

“The idea here is to have a vaccine that will give people a baseline level of immune memory for different flu strains so that there will be much less illness and death when the next flu pandemic happens,” said study leader Scott Hensley of the Perelman School. of Medicine at the University of Pennsylvania said in a statement.

Unlike standard flu vaccines that release one or two versions of hemagglutinin, the experimental vaccine contains 20 different strains in the hope that the immune system will recognize any flu virus it might encounter in the future.

In laboratory experiments, the immune system of vaccinated animals recognized the hemagglutinin proteins and defended against 18 different strains of influenza A and two strains of influenza B. Vaccine-induced antibody levels remained unchanged for at least four months, according to a report published in the journal Science.

The vaccine reduced symptoms and protected against death, even when the ferrets were exposed to a different type of flu not included 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 early-stage human safety trials. These vaccines are designed to defend against just four recently circulating flu strains, but could theoretically be changed every year.

The universal flu vaccine, if successful in human trials, would not necessarily prevent infection. The goal is to provide lasting protection against serious illness and death, Hensley said.

Questions remain about how to assess the efficacy and potential regulatory requirements for a vaccine against potential future viruses not currently circulating, wrote Alyson Kelvin and Darryl Falzarano of the University of Saskatchewan, Canada, in a commentary published in conjunction with the study. published.

While the promising results with the new vaccine “suggest a protective ability against all subtypes of flu viruses, we can’t be sure until clinical trials in volunteers are done,” said Adolfo GarcĂ­a-Sastrem, director of the Institute for Global Health and Emerging Pathogens at Mount Sinai Hospital in New York, it said in a statement.

Reporting by Nancy Lapid; Edited by Christine Soares and Bill Berkrot

Our Standards: The Thomson Reuters Principles of Trust.

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