The flu virus is a crafty foe, constantly adapting to our best weapons. It's an arms race every year, as scientists need to go back to the drawing board and predict how the virus might change. But now we might be gaining the upper hand in the war: a universal flu vaccine has been cleared for widespread human trials in the UK that should be much more effective at destroying different forms of the virus.

The flu might seem common and largely harmless, but the virus is not to be underestimated: the illness spreads easily and in severe cases can annually cause up to half a million deaths worldwide, particularly in people over the age of 65. Every year, it's a race for scientists to develop and deliver vaccines to fight the strains predicted by the World Health Organization to be the most likely to circulate. Unfortunately, the constantly-adapting bug often has other plans, with different strains spreading and undermining the vaccine's effectiveness – that's why you might still get the flu after getting the jab.

Previous research into a universal flu vaccine has uncovered the mechanism by which immune cells remember which strains they've already encountered, and an antibody that's particularly good at neutralizing different strains.

Most vaccines work by spurring the immune system to produce more antibodies tuned towards surface proteins found on the outside of the flu cell. The problem is, these proteins tend to change every year, sending scientists back to the drawing board. Instead, the new vaccine, developed by Oxford University and a spin-off company called Vaccitech, fights the flu by making use of core proteins found deeper inside the flu cell, which stay largely the same across different strains.

As an added protection, the new vaccine also has a different effect on the immune system. Rather than antibodies, the drug leads to the production of more influenza-targeting T cells, which are more potent soldiers against the virus and can attack different types of the flu. Hopefully, this means that the vaccine will protect people from a wider range of strains of Influenza A, the most dangerous of the two human-infecting types. For the unlucky few who still get the flu post-shot, the illness should be shorter and less severe.

Human trials are due to begin in the UK this winter, involving an expected sample of at least 500 people over the age of 65, since they are the most at-risk group. Of those, 25 people will be selected to undergo extra blood tests, receiving the regular annual immunization along with either the new vaccine or a placebo shot, in order to compare the two.

"Every year, flu in older adults causes serious illness and sometimes death," says Sarah Gilbert, Professor of Vaccinology at Oxford and co-founder of Vaccitech. "We want to improve the situation, but in order to do that we need volunteers to help us test a new vaccine. If you are invited to take part, please consider doing so."

Source: Oxford University