A VACCINE nose spray containing a bug that causes food poisoning might be more effective than injections at preventing flu.
The spray contains a flu vaccine mixed with the Escherichia coli (E. coli) bacterium, which can lead to severe stomach cramps, diarrhoea and vomiting.
The addition of E. coli helps trigger a larger immune system response to the virus than existing flu jabs. Using this spray directly in the nose lining can prime the immune system to block the virus for up to six months, according to a study from researchers at the National Taiwan University Hospital.
By acting directly on the nose and throat, the spray encourages production of more antibodies at the point where the flu virus typically invades the human body, they said.
Results of the trial, involving 350 patients, show the vaccine is safe and effective, triggering a greater immune response than a conventional flu vaccine.
Flu causes a relatively mild illness in most people, but it can travel to the lower respiratory system, resulting in fatal pneumonia in severe cases - particularly among vulnerable groups, including people over 65 and those with underlying health conditions. More than 20,000 in the UK died from flu in 2017-18.
Flu vaccines are estimated to have prevented between 15 to 52 per cent of flu cases between 2015 and 2020. But effectiveness varies.
Flu jabs - usually made with inactivated viruses - trigger the production of antibodies.
Nasal spray versions, which avoid needles, contain live viruses that are weakened so they will not cause illness yet marshal a greater immune response (including more sophisticated T-cells and B-cells) - and, in the case of respiratory infections, can be delivered straight to where viruses replicate.
But nasal sprays aren't always effective, not least because it is harder to tell how much of the vaccine has been delivered.
The spray, developed by Taiwan-based Advagene Biopharma, contains a flu vaccine wrapped in detoxified (harmless) E. coli. The idea is that in mounting a response to the bacteria, the body also creates more antibodies to the flu virus.
The research, reported in the journal Vaccine, showed those using the spray had higher amounts of antibodies in their blood than those given a control vaccine injection.
Greg Towers, a professor of molecular virology at University College London, said: "All vaccines contain a component called an adjuvant to activate the immune system. Here the adjuvant is derived from E. coli - a great immune activator - so this works well.
"A nasal response is also expected to be more effective if driven by the right antigen in the right place - the nose and airway - than when given in the arm," he adds, explaining that "the nose is evolved to be a protective barrier and, as such, the immunity one can induce here is particularly effective".
© Daily Mail
