Nov 24 (Reuters) – An experimental vaccine provided broad protection against all 20 known subtypes of influenza A and B viruses in preliminary tests on mice and ferrets, according to a U.S. agency, The study, published Thursday, could open the way for a universal flu vaccine that could help prevent future pandemics.
The two-dose vaccine uses the same messenger RNA (mRNA) technology as the COVID-19 vaccine being developed by Pfizer (PFE.N) with BioNTech (22UAy.DE) and Moderna (MRNA.O). It delivers tiny lipid particles containing mRNA instructions for cells to produce copies of a protein called hemagglutinin that appears on the surface of influenza viruses.
A universal vaccine would not spell the end of flu season, but would replace the guesswork of developing an annual vaccine in the months leading up to each flu season.
Scott Hensley, head of the study at the Perelman School, said: “The idea here is to create a vaccine that gives people a baseline level of immune memory against different strains of flu so that when the next flu pandemic hits , the number of illnesses and deaths would be greatly reduced,” Penn MD said in a statement.
Unlike the standard flu shot, which offers one or two versions of the hemagglutinin, the experimental vaccine includes 20 different types, hoping to allow the immune system to recognize any flu viruses it might encounter in the future.
In laboratory experiments, the immune systems of vaccinated animals recognized the hemagglutinin protein 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 study published in the journal Science.
Even when ferrets were exposed to another type of flu other than the vaccine, the vaccine reduced signs of illness and prevented deaths, the researchers said.
Both Moderna and Pfizer have mRNA flu vaccines in late-stage human trials, and GlaxoSmithKline (GSK.L ) and partner CureVac (5CV.DE ) are testing mRNA flu vaccines in early-stage safety trials in humans. The vaccines are designed to protect against the four most recent circulating flu strains, but could theoretically be changed every year.
Even if the universal flu vaccine is successful in human trials, it may not necessarily prevent infection. The goal is to provide durable protection against severe disease and death, Hensley said.
Alyson Kelvin and Darryl Falzarano of the University of Saskatchewan in Canada wrote in a commentary accompanying the study about how to judge whether a vaccine is Questions remain about the efficacy and potential regulatory requirements of possible future viruses that have not yet spread.
While the promising results for the new vaccine “suggest that it has protection against all influenza virus subtypes, we cannot know for sure until clinical trials in volunteers are completed,” said Adolphe García, director of the Institute for Global Health and Emerging Pathogens at the University of Montreal – Adolfo García-Sastrem New York-Sinai Hospital said in a statement.
Reporting by Nancy Lapid; Editing by Christine Soares and Bill Berkrot
Our Standards: The Thomson Reuters Trust Principles.