Researchers are testing mRNA technology for universal flu vaccine

NOVEMBER 24 (Reuters) – An experimental vaccine offered broad protection against all 20 known subtypes of influenza A and B viruses in initial tests in mice and ferrets, potentially paving the way to a universal flu shot that could help to prevent future pandemics, according to the USA study published on Thursday.

The two-dose vaccine uses the same messenger RNA (mRNA) technology used in the COVID-19 vaccines developed by Pfizer (PFE.N) with BioNTech (22UAy.DE) and Moderna (MRNA.O). It delivers tiny lipid particles that contain mRNA instructions for cells to make copies of proteins called hemagglutinin that appear on influenza virus surfaces.

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

“The idea here is to have a vaccine that gives people a baseline level of immune memory for different strains of flu so that there will be far fewer illnesses and deaths in the next flu pandemic,” said study leader Scott Hensley of the Perelman School of Medicine the University of Pennsylvania said in a statement.

Unlike standard flu vaccines, which provide one or two versions of hemagglutinin, the experimental vaccine includes 20 different types in hopes of tricking the immune system into recognizing any flu virus it might encounter in the future.

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

The vaccine reduces signs of illness and protects against death even if the ferrets have been exposed to another type of flu that wasn’t in the vaccine, the researchers said.

Moderna and Pfizer both have mRNA flu vaccines in late-stage human trials, and GSK (GSK.L) and its partner CureVac (5CV.DE) are testing an mRNA flu vaccine in an early-stage human safety trial. These vaccines are designed to protect against only four recently circulating influenza strains, but could theoretically be replaced 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 assessing the efficacy and potential regulatory requirements for a vaccine against possible future viruses that are not currently in circulation, wrote Alyson Kelvin and Darryl Falzarano of the University of Saskatchewan, Canada, 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 have been conducted in volunteers,” said Adolfo GarcĂ­a-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; Edited by Christine Soares and Bill Berkrot

Our standards: The Thomson Reuters Trust Principles.

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