Existing flu vaccines prompt the immune system to create antibodies that recognise structures on the surface of the virus. But the flu virus can quickly change in subtle ways which allow it to evade the immune system and means potentially-dangerous new strains of the virus can emerge.
“New strains of flu are continuously emerging, some of which are deadly, and so the Holy Grail is to create a universal vaccine that would be effective against all strains of flu,” said Prof Lalvani who led the large research team behind the study.
At the moment, the composition of the seasonal flu vaccine is reviewed every year by the World Health Organisation (WHO). A network of experts determines the make-up of the annual vaccine based on the most commonly circulating strains of the flu virus.
The new research, published by Nature Medicine, a respected scientific journal, takes a different approach to protecting the population against influenza.
More than 300 staff and students at Imperial College London were recruited for the study at the beginning of the 2009 influenza pandemic and monitored throughout the outbreak.
It was found that people who avoided severe illness had more CD8 T cells, a kind of virus-killing cell, in their blood at the start of the pandemic. This could, say researchers, hold the key to developing new ways of protecting against the flu.
“We already know how to stimulate the immune system to make CD8 T cells by vaccination,” Prof Lalvani said. “Now that we know these T cells may protect, we can design a vaccine to prevent people getting symptoms and transmitting infection to others. This could curb seasonal flu annually and protect people against future pandemics.”
The findings have been welcomed but there is also some scepticism among scientists about whether the kind of T-cell vaccine suggested by the researchers could offer long-lasting protection.
Prof John Oxford of Queen Mary University in London told the BBC that the new research “is not going to solve all the problems of influenza but it could add to the range of vaccines”.
“It’s going to be a long journey from this sort of [research] paper to translating it into a vaccine that works,” he said.
In the meantime, winter is approaching and flu viruses are back in circulation in Europe. People in high risk groups – such as pregnant women, older people, and those with chronic illnesses – are advised to ask their healthcare provider about the annual flu vaccination.