A “universal” influenza vaccine has been constructed out of nanoparticles by scientists using a technique which it is hoped could at last lead to effective winter flu jabs.

The vaccine, which has been successfully tested on mice, is designed to protect against a broad range of variants of the disease, by training the immune system to spot core and unchanging features of the virus.

It will still have to overcome many hurdles before it could be approved for use on humans but researchers said that it was at the very least proof of the principle of a new way of engineering vaccines. By building the vaccine using nanotechnology, the scientists hope that they could one day adapt the technique to target precisely a wide range of pathogens.

However, other scientists suggested that it was still not completely clear how the vaccine was working and whether it might have unwanted side-effects.

Flu is one of the most difficult viruses to stop, in part because it evolves so rapidly. Each year, at-risk populations such as the elderly are offered a vaccine containing the strains that doctors believe will be circulating that winter but it is never more than partially effective. Even if a vaccine does work, it rarely offers any immunity at all a year later because of the fast-changing nature of flu.

Several groups are now trying to develop universal vaccines, in which people’s immune systems are harnessed to attack parts of the flu virus that don’t change — the quintessence of flu. The latest study, published in the journal Proceedings of the National Academy of Sciences, does so by using a method that scientists hope can be generally applied.

Researchers used compounds called peptides to build up a cluster of particles containing structures that mimicked the “evolutionarily conserved” parts of flu viruses.

Baozhong Wang, from Georgia State University, said that in this way they were able to stay ahead of the virus. “Influenza is hard to combat because it is a moving target,” he said. “They change their major antigens rapidly to evade existing immune responses in humans.”

The vaccine was administered using a “microneedle” patch, which is theoretically painless and which they hoped could be easier to use in humans. Dr Wang said that he was very hopeful of developing a treatment. “No doubt, these findings will open a new vision for the development of an affordable universal influenza vaccine,” he said.

The research showed that this was enough to maintain protection in mice. Dr Wang said that he now hoped to test the vaccine in other animals before bringing it to clinical trials in humans.

Daniel Davis, professor of immunology at Manchester University, said that one of the key questions was whether the vaccine would cause side-effects. By training the body to attack a more generic part of the flu virus, it was possible that the immune system could also attack necessary proteins. He also said, however, that the study showed the field of nanotechnology was a promising area in vaccine research.

“There is a realistic hope that some type of nanotech could yield a new and exciting way for vaccines to be delivered,” said Professor Davis, author of The Beautiful Cure, which discusses new ways to make vaccines.

“The research here offers one specific approach — using small clusters of a protein motif common to several types of influenza virus — but the work is still at an early research phase. We don’t yet know whether or not this idea would work in people or whether or not it would cause unwanted side-effects for example.”

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