A flu vaccine that protects against all strains of the virus could be available in the next two years, according to a leading scientist.
An experimental vaccine based on the same mRNA technology that was used in the highly successful Covid jabs was found to protect mice and ferrets against severe influenza, paving the way for clinical trials in humans.
Professor John Oxford, a neurologist at Queen Mary University in London who was not involved in the work, said the vaccine developed at the University of Pennsylvania could be ready for use in the winter after next.
Oxford told the BBC's Radio 4 Today programme that they could not emphasise enough what a breakthrough this paper is. The potential is huge, and I think sometimes we underestimate these big 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 towards a jab that could protect humans from a potentially devastating flu epidemic.
Seasonal flu vaccines, which protect against up to four strains of the virus, are updated every year to make sure they are a good match for flu viruses in circulation. The vaccine is designed to prime the immune system against all 20 subtypes of influenza A and B, potentially arming the body to tackle any flu virus that comes along with it.
In 2009, the world had a flu epidemic when a virus that jumped from pigs to humans spread around the world. The 1918 flu pandemic showed how dangerous new strains could kill tens of millions of people, despite the fact that the outbreak was less deadly than health officials feared.
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 epidemic happens, according to Dr Scott Hensley, a researcher on the team in Pennsylvania. Experiments in mice and ferrets found that the mRNA flu vaccine resulted in high levels of antibodies that were stable for several months and protective against the virus.
Clinical trials are needed to see if the vaccine protects humans in the same way without causing problems with side-effects, despite the promising results from the animal tests. The vaccine raises questions for regulators about whether or not to approve a shot that could protect against viruses with potential, but hasn't yet emerged.
The vaccine has been tested in animals and it will be important to investigate its safety and efficacy in humans, said Andrew Freedman, a reader in infectious diseases at Cardiff University. It seems to be a very 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 rhino and corona-viruses. Adolfo Garc a-Sastre, the director of the Institute for Global Health and Emerging Pathogens at Mount Sinai Hospital in New York, said current influenza vaccines did not protect against influenza viruses with pandemic potential. This vaccine, if it works well in people, would achieve this. He added that the studies are preclinical, in experimental models. They are very promising and we can't be sure until clinical trials are done, because they suggest a protective capacity against all subtypes of influenza viruses.