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 injections has been found to protect mice and ferrets from severe flu, paving the way for human clinical trials.
Prof. John Oxford, a neuroscientist 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 cannot stress enough what a 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 seen as an important step toward a shot 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 appropriate for circulating flu viruses. 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 arises.
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 epidemic 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 a “baseline” level of immunity against the full range of flu strains could lead to much less illness and fewer deaths when the next flu pandemic hits, said Dr. Scott Hensley, a researcher with the Pennsylvania team. Experiments with mice and ferrets found that the mRNA flu vaccine provoked 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 troublesome side effects. The vaccine raises questions for regulators about whether to approve an injection that could protect against viruses with pandemic potential but which have yet to emerge in reality.
“This vaccine has so far only been tested in animals and it will be important to study its safety and efficacy in humans,” said Dr Andrew Freedman, Reader in Infectious Diseases at Cardiff University. “This really looks like a very promising approach to the goal of producing a universal flu vaccine, as well as vaccines that protect against multiple members of other virus families, such as rhino and corona viruses.”
Adolfo Garcia-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, will achieve that.”
“The studies are preclinical, in experimental models,” he added. “They are very promising, and although they suggest a protective capacity against all subtypes of influenza viruses, we cannot be sure until clinical trials are done in volunteers.”
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