A universal flu vaccine that protects against all strains of the virus could be available within the next two years, according to a leading scientist.
An experimental vaccine based on the same mRNA technology used in Covid-19 shots was found to be highly successful in protecting mice and ferrets against severe flu, paving the way for clinical trials in humans.
Professor John Oxford, a virologist at Queen Mary University of London, who was not involved in the work, said the vaccine developed at the University of Pennsylvania could be ready for use by next winter.
“I can’t stress enough what a huge breakthrough this document is,” Oxford told the BBC’s Radio 4 Today programme. “The potential is huge, and I think we sometimes underestimate these big respiratory viruses.”
Researchers have been working on universal flu vaccines for more than a decade, but the latest breakthrough, published in Science, is considered a major step toward a shot that could help protect humans from a potentially pandemic flu devastating
Seasonal flu vaccines, which protect against up to four strains of the virus, are updated every year to ensure they are a good match for the flu viruses in circulation. The new vaccine is designed to prime the immune system against all 20 subtypes of influenza A and B, potentially arming the body to deal with any flu virus that emerges.
The world last experienced a flu pandemic in 2009 when a virus that jumped from pigs to humans spread across the globe. Although this outbreak was far less lethal than health officials had feared, the 1918 flu pandemic showed how dangerous new strains could kill tens of millions of people.
Giving people a “baseline” level of immunity against the full range of flu strains could lead to far less illness and fewer deaths when the next flu pandemic hits, said Dr Scott Hensley, a researcher on the team in pennsylvania Experiments in mice and ferrets found that the mRNA flu vaccine elicited high levels of antibodies that were stable for several months and protective against the virus.
Although results from animal tests are promising, clinical trials are needed to see if the vaccine protects humans in the same way without causing troublesome side effects. The vaccine raises questions for regulators about whether to approve a vaccine that could protect against viruses with pandemic potential, but which have yet to emerge.
“This vaccine has only been tested in animals so far and it will be important to investigate its safety and efficacy in humans,” said Dr Andrew Freedman, Reader in Infectious Diseases at Cardiff University. “This appears to be a very promising approach for the goal of producing a universal influenza vaccine, as well as vaccines that protect against various members of other viral families, such as rhino and corona viruses.”
Adolfo García-Sastre, director of the Institute for Global Health and Emerging Pathogens at Mount Sinai Hospital in New York, said current flu vaccines do not protect against influenza viruses with pandemic potential. “This vaccine, if it works well in people, would make it.”
“The studies are preclinical, in experimental models,” he added. “They are very promising, and although they suggest a protective ability against all subtypes of the flu virus, we cannot be sure until clinical trials are done in volunteers.”