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 has been found to protect mice and ferrets from severe flu, paving the way for human clinical trials.
Professor 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 how ground-breaking this documentary is,” Oxford told BBC Radio 4’s Today programme. “The potential is huge and I think sometimes we underestimate these large respiratory viruses.”
Scientists have been working on universal flu vaccines for more than a decade, but the latest breakthrough, published in Science, is seen as a major 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 the virus, are updated each 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 last time the world experienced a flu pandemic was in 2009, when a virus that jumped from pigs to humans spread around the world. While this outbreak was far less deadly 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 a range of flu strains could lead to far fewer illnesses and fewer deaths when the next flu pandemic occurs, said Dr Scott Hensley, a researcher with the team in Pennsylvania. Experiments in mice and ferrets found that the mRNA flu vaccine induced high levels of antibodies that were stable for several months and protected against the virus.
While animal test results are promising, clinical trials are needed to see if the vaccine protects humans in the same way without causing problematic side effects. The vaccine is raising questions for regulators about whether to approve an injection that could protect against viruses with pandemic potential but which haven’t actually appeared 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, Reader in Infectious Diseases at Cardiff University. “This seems like a very promising approach to the goal of making a universal flu vaccine, as well as vaccines that protect against multiple members of other viral families, such as rhinoviruses and coronaviruses.”
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 humans, would achieve that.”
“The studies are preclinical, in experimental models,” he added. “They are very promising, and although they suggest a protective ability against all subtypes of influenza viruses, we can’t be sure until clinical trials are done in volunteers.”