A universal flu vaccine could be available as early as 2024, one of the UK’s top experts has predicted.
An experimental vaccine provided broad protection against all 20 known influenza A and B virus subtypes in initial tests in mice and ferrets.
It potentially opens a pathway to a universal flu shot that might help prevent future pandemics, according to a US study published on Thursday.
The two-dose vaccine employs the same messenger RNA (mRNA) technology used in the Covid-19 shots developed by Pfizer with BioNTech, and by Moderna.
It delivers tiny lipid particles containing mRNA instructions for cells to create replicas of so-called hemagglutinin proteins that appear on influenza virus surfaces.
A universal vaccine would not mean an end to flu seasons, but would replace the guess work that goes into developing annual shots months ahead of flu season each year.
John Oxford, Professor of Neurology at Queen Mary University, was asked if it could be ready for next winter, and he told the BBC’s Radio 4 Today programme: “I think it’ll be stretching it but I would go for – I’m not a betting person – but I’ll put my cash on the winter afterwards.
“But we’ll have it and I cannot emphasise enough what a breakthrough this paper is.
“The two beasts of the jungle, the respiratory jungle, flu and Covid, they can be gripped I think by this new technology of mRNA vaccines, and that will help us tremendously in the years ahead.”
The vaccine would still need to be updated annually to take in the new strains for a broad protection, but Prof Oxford said it would save many thousands of lives.
“I mean, look at the potential what’s happened with the Covid I mean, how many people have died, but how the vaccines have saved them.
“So the potential is huge, and I think sometimes we underestimate these big respiratory viruses, I really do.
“So we have to get a grip on it, we’ve almost got a grip I think on the Covid, and I think now the influenza is the next big beast out there to tackle.”
Unlike standard flu vaccines that deliver one or two versions of hemagglutinin, the experimental vaccine includes 20 different types in the hope of getting the immune system to recognize any flu virus it might encounter in the future.
In lab experiments, vaccinated animals’ immune systems recognized the hemagglutinin proteins and defended against 18 different strains of influenza A and two strains of influenza B.
Antibody levels induced by the vaccine remained unchanged for at least four months, according to a report published in the journal Science.
The vaccine reduced signs of illness and protected from death even when the ferrets were exposed to a different type of flu not in the vaccine, the researchers said.
Moderna and Pfizer both have mRNA flu vaccines in late-stage human trials, and GSK and partner CureVac are testing an mRNA flu vaccine in an early-stage safety trial in humans.
These vaccines are designed to defend against only four recently-circulating influenza strains but could theoretically be changed up each year.
The universal flu vaccine, if successful in human trials, would not necessarily prevent infection.
Study leader Scott Hensley of the Perelman School of Medicine at the University of Pennsylvania said: “The idea here is to have a vaccine that will give people a baseline level of immune memory to diverse flu strains, so that there will be far less disease and death when the next flu pandemic occurs.”
The goal is to provide durable protection against severe disease and death, Mr Hensley said.
Questions remain regarding how to judge efficacy and potential regulatory requirements for a vaccine against possible future viruses that are not currently circulating, Alyson Kelvin and Darryl Falzarano of the University of Saskatchewan, Canada, wrote in a commentary published with the study.
While the promising results with the new vaccine “suggest a protective capacity against all subtypes of influenza viruses, we cannot be sure until clinical trials in volunteers are done,” Adolfo García-Sastrem, director of the Institute for Global Health and Emerging Pathogens at Mount Sinai Hospital in New York, said in a statement.