Oxford University scientists said they were pleased with the response after 80 people responded to a plea for volunteers to test a new vaccine against the potentially deadly H5N1 strain of bird flu.

Scientists from the university's Oxford Vaccine Group are hoping to recruit enough people - including 75 who are over 60 - to test two new vaccine formulations in case bird flu should spread to humans in this country.

There are 15 types of bird flu and the most contagious strains, which are usually fatal in birds, are H5 and H7. Strain H5N1 can prove fatal to humans. Migratory wildfowl, such as wild ducks, are natural carriers of the viruses, but they are unlikely to develop an infection.

The risk is that they pass it on to domestic birds, such as chickens, which are much more susceptible.

Bird flu was thought only to infect birds until the first human cases were seen in Hong Kong in 1997.

It has been forecast that if there were an epidemic in this country, up to 50,000 people could die.

Senior research nurse Tessa Waterhouse said: "We are very pleased. We didn't really have any idea how people would respond.

"We will start enrolling people on Monday, and we urge more volunteers to come forward in the meantime."

The Oxford study, which will run alongside three trials in Belgium, is the second of its kind in Europe.

The vaccine has already been successfully tested on 300 adults in France.

It does not have any serious side-effects, other than the possibility of sore arms and a high temperature.

The study involves volunteers having a vaccination, a second dose three weeks later and a booster jab within a year, with up to seven visits to the Churchill Hospital in Headington over 12 or 18 months.

Volunteers will not be paid but will have their expenses reimbursed.

To volunteer for the trial, or to obtain further information, call 01865 857420.