SCIENTISTS are one step closer to a universal "one-hit wonder" flu jab that can protect against ALL strains of the nasty virus.
The new vaccine protects against lethal doses of seven to nine different influenza strains, new findings reveal.
And mice that received the higher doses of the experimental jab didn't even fall ill with symptoms of the flu.
Meanwhile, rodents that were given the traditional flu shot or nasal sprays all got sick and died when they were exposed to the same, lethal strains.
In those animals the deadly bugs were able to outsmart the immune responses triggered by the traditional vaccines.
While it could be years before it could be used successfully in humans, the scientists at the University of Nebraska-Lincoln said it is a "promising" step in the right direction.
Dr Eric Weaver, said the study is the first to show a universal flu shot could be created from genes shared by ancestral strains of the flu virus.
"The ultimate goal is to be able to vaccine once and provide lifelong protection," Dr Weaver said.
In the US, health officials estimate 40 million people caught flu during the 2015-16 season, and 970,000 Americans were hospitalised with the illness.
The Centers for Disease Control and Prevention said they believe vaccinations prevented about 1.9 million illnesses and 67,000 hospitalisations.
Dr Weaver said: "To put this in other terms, our current influenza vaccine programs and technologies reduce influenza infections and hospitalizations by 4.75 percent and 6.9 percent, respectively.
"There is no doubt that there is a need for more effective vaccine technologies."
It comes as the NHS braces itself for one of the worst flu seasons amid fears a brutal outbreak in Australia could be heading for British shores.
But, because the flu virus mutates very quickly and many people, animals and birds can carry the virus without showing symptoms, it has proved difficult to create a vaccine that is effective in the long-term.
The ultimate goal is to be able to vaccine once and provide lifelong protectionDr Eric Weaver
The current jab uses weak or dead versions of the flu virus to stimulate the immune system, triggering protection against a protein called haemagglutinin (HA), which extends from the virus and attacks the body's cells.
A piece of research published in 2013, revealed one of the main problems with the flu jab each year, is scientists have to predict which flu strains will rear their ugly heads in the coming years.
They do so by looking at the strains that have already hit in recent years.
Dr Weaver said: "An ideal influenza vaccine would be inexpensive, provide long-lasting immunity, require few immunisations and would work against all variants of the virus."
That universal, "one jab kills all" dream is unlikely to be available before at least 2020 or 2025, scientists predict.
Dr Weaver said his team's findings and approach is "scalable and translatable to humans and may provide the foundation for complete and long-lasting anti-influenza immunity".
Their experiments followed similar research, Dr Weaver took part in, in the past to try and find a cure for HIV.
It saw Dr Weaver's team try and pinpoint the genes at the very core of the flu virus, those that run through all strains.
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Instead of using weak or deadened flu virus, their experiments used altered adenoviruses, that cause the common cold.
The viruses were altered to carry the core genes for H1, H2, H3 and H5 influenza strains.
And they found unlike the conventional jabs, the new version doesn't make people sick with flu symptoms, but still delivered the vaccine genes safely.
Dr Weaver added: "Our idea is that these centralised antigens can set up a foundation of immunity against influenza.
"Because they are centralised and represent all the strains equally, they could provide a basis for immunity against all evolved strains."