Tuesday, October 5, 1999 Published at 13:00 GMT 14:00 UK
Scientists develop lifelong flu vaccine
Current flu vaccines do not last long
An experimental vaccine could one day immunise people for life against dangerous forms of the flu virus, scientists hope.
Vaccines currently on the market protect against only 80% of cases and usually last for only one year.
They can be rendered ineffective by the emergence of new strains of the flu virus.
The new vaccine has been developed by scientists in Belgium headed by Emeritus Professor Walter Fiers, who said the vaccine had been tested on animals, but not as yet on humans.
He said: "If all goes well you could obtain lifelong protection. It would be similar to a polio vaccine or hepatitis: in childhood you have an immunisation and you are then protected against influenza A for the rest of your life."
Vaccines work by alerting the body's immune system to the threat posed by a virus or bacterium so that it can respond by producing antibodies to fight the invader.
The difficulty with finding an efficient vaccine against flu is that the virus changes shape constantly. So a new vaccine is needed every winter.
Professor Fiers' team say they have found a piece of the virus that never changes shape, however much the rest of the organism mutates.
The body's immune system learns to attack that fragment - a protein called M2 - and fend off the virus.
Professor Fiers said early work showed the vaccine could be administered through the nose.
"It is easier, especially if you have children, by doing it with droplets in the nose rather than by injection."
The work is based on experiments on mice which have immune systems very similar to those of humans.
It will take several more years of work on humans before an influenza vaccine might become available.
But when one does, it could have a huge commercial impact.
In the US, Britain and Japan alone, an estimated 120 million people catch flu every year.
The breakthrough comes just after the National Institute for Clinical Excellence blocked the use of new flu drug Relenza on the NHS in the UK on the grounds that its effectiveness for elderly patients had not been proven.
Glaxo Wellcome, which manufactures Relenza, is considering legal action against the government and has warned that leading drugs companies will consider pulling out of Britain if ministers adopt an "antagonistic" attitude towards the pharmaceutical industry.
Professor Ron Eccles, director of the Common Cold Centre in Cardiff, said the vaccine could be a major breakthrough.
He said: "If they have got something that does offer lifelong protection it would be a major revolution in treating flu and could dramatically change a lot of public health.
"If patients can just have one vaccine, logistically that would be so much easier than trying to get all those at risk to be vaccinated every year."
Those most at risk from flu include people aged over 75, those with a weakened immune system and those with a chronic heart or respiratory condition.