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 the highly successful Covid jabs, was found to protect mice and ferrets against severe flu, paving the way for human clinical trials.
Prof John Oxford, a neurologist 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 next winter.
“I can’t stress enough what a breakthrough this article is,” Oxford told the BBC’s Radio 4 Today. “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 seen as an important step toward a jab that could help protect people from a potentially devastating flu pandemic.
Seasonal flu vaccines, which protect against up to four strains of virus, are updated each year to ensure they are a good match for 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 around the world. While that outbreak was much less deadly than health officials 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 much less illness and fewer deaths in the next flu pandemic, said Dr. Scott Hensley, a researcher on the team in Pennsylvania. Experiments on mice and ferrets showed that the mRNA flu vaccine elicited high levels of antibodies that were stable for several months and protective against the virus.
While the results from the animal trials are promising, clinical trials are needed to see if the vaccine protects humans in the same way without causing problematic side effects. The vaccine raises questions from regulators about whether or not to approve an injection that could protect against viruses with pandemic potential, but which have not really surfaced yet.
“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, a reader in infectious diseases at Cardiff University. “It appears to be a promising approach to the goal of producing a universal flu vaccine, as well as vaccines that protect against multiple members of other viral families, such as rhinoceros and coronaviruses.”
Adolfo García-Sastre, the 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 flu viruses with pandemic potential. “This vaccine, if it works well in humans, would achieve this.”
“The studies are preclinical, in experimental models,” he added. “They show promise and while they suggest protective potential against all subtypes of influenza viruses, we can’t be sure until clinical trials in volunteers are done.”