Hundreds of thousands of asthma sufferers could be spared from a severe or potentially fatal attack by a scientific breakthrough.

Research published in the journal Nature Medicine shows asthmatics only produce half the number of anti-viral proteins when suffering a cold that non-sufferers do. As a result, they are far more likely to suffer a severe attack during a cold - and even end up in hospital. About 1,500 sufferers die every year.

Figures from Asthma UK show that 60 per cent of adults and 80 per cent of children taken to hospital as a result of an attack are suffering from a viral infection.

But researchers believe inhalers can be developed to deliver the necessary anti-viral medicine to the lungs to help the body fight back. Professor Sebastian Johnston, of Imperial College London and the Medical Research Council's Asthma UK Centre, said he was excited by the findings.

"People with asthma are particularly susceptible to rhinoviruses - which are the major cause of severe asthma attacks," he said.

"When we tested volunteers with and without asthma we found these new interferons, which would tackle the infection, were not being produced as effectively in people with asthma.

"Delivery of the deficient interferons by inhalers could be an ideal way to treat and prevent severe attacks of asthma, potentially vastly improving the quality of life for asthma patients."

Lyn Smurthwaite, research development officer for Asthma UK, added: "For people with asthma, even a common cold can result in hospital treatment - yet no specific treatment is available to help virally induced asthma attacks." On average, 198 people a day were admitted to hospital with asthma attacks.

Ms Smurthwaite said Asthma UK was "delighted" to have funded research leading to the breakthrough.

Helena Shovelton, chief executive of the British Lung Foundation, which also helped fund the study, said: "The results will be of invaluable help in improving the treatment and care of people with asthma. Professor Johnston and his colleagues have identified a reason why people are more susceptible to rhinovirus infections which can cause asthma attacks. This important finding paves the way for developing new approaches to prevention and treatment."

About 5.2 million people in the UK - roughly one in 12 of the population - receive treatment for asthma.