Drug company Moderna says its combined flu and Covid vaccine, which targets the two diseases in a single shot, has passed a vital part of final-stage scientific checks.
The phase-three trial shows the vaccine arms the body with protective antibodies.
And it does so as effectively as separate flu and Covid shots, results suggest.
Fewer injections would be more convenient and simpler, Moderna says.
Chief executive Stephane Bancel told BBC News he hoped the messenger ribonucleic acid (mRNA) vaccine could be made widely available in 2026 – or perhaps, 2025.
“We are very delighted about the results, because it’s the first time in the world that a company is able to show positive phase-three results combining in a single dose flu and Covid vaccine,” he said.
“You get one dose, one needle,” which meant “ease and peace of mind for the consumer”.
Competitors Pfizer and BioNTech are testing a similar two-in-one mRNA vaccine against flu and Covid.
Scientists hope mRNA vaccines will be faster to make and update than the current ones used against flu, and be a better match for ever-changing strains.
In the continuing Moderna trial, the mRNA-1083 jab produced a higher immune response than the licensed comparator vaccines.
It matched or bettered currently approved flu jabs, including high-dose ones designed for older people.
And it was better than Moderna’s existing Covid booster, Spikevax, at making the body produce disease-fighting antibodies – probably because it had been designed to fight more recent variants circulating around the world, Mr Bancel told BBC News in an interview.
