An anti-flu drug currently under trial in the US may provide a way of stemming a future epidemic of the bug.

The virus-suppressing drug, pleconaril, has been developed by ViroPharm and researchers at the University of Virginia.

It was originally developed to treat diseases such as meningitis and polio - but is also being used to help reduce the duration of the common cold and flu.

More tests

The drug is in its final trial stages before seeking a US licence - and would have to undergo more trials in the UK if it were to be used here.

Scientists at the University of Virginia in found that it could knock an average of three and a half days off a two-week cold.

They tested the drug on 1,024 people aged 14 and over who were suffering a cold.

Patients who got the drug suffered the illness for an average of 11.5 days, compared with 14 days for those given dummy pills.

Dr Frederick Hayden presented his team's findings at the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Francisco in Autumn last year.

He said the drug seemed very safe, with few apparent side effects.

The patients it was tested on were suffering viral respiratory infection - a serious form of the common cold that causes fevers, coughs, muscle aches, tiredness and a runny nose.

It can also cause ear infections and develop into bronchitis.

Concerns

Other studies have shown that the drug is effective at cutting the course of a viral meningitis infection by two to three days.

In May 1999, researchers announced that they could disrupt one of the viruses behind the disease before it took hold on the body.

However, there were concerns that the method used - spraying an artificially-produced molecule into the nose and throat - might have toxic effects.

A medical solution to the common cold has been impossible to find mainly due to the high numbers of constantly changing viruses. There are at least 100 different types of rhinovirus.

Because of this, cold vaccines have had only limited success, as have other treatments that attack the viruses responsible.