The government has been urged to vaccinate the population against bird flu in the face of a possible global pandemic.
Experts said the World Health Organization and national governments should give "urgent consideration" to a campaign involving an initial vaccination to build up the immune system followed by a booster shot as soon as the first signs of a pandemic emerge. People primed in advance would then be fully protected in a week instead of six weeks.
Writing in the journal The Lancet Infectious Diseases, a team of international researchers says there may be no warning before the deadly H5N1 bird flu explodes in the human population.
Scientists fear a pandemic could occur if the virus mutates and acquires the ability to transfer directly between people. So far every victim of the virus is thought to have been in contact with infected birds.
Current vaccination strategies require two jabs spaced six weeks apart. But the experts, who include Professor Karl Nicholson, from the University of Leicester, warn that after six weeks it may be too late to prevent widespread loss of life.
Estimates of the effects of a bird flu pandemic have suggested that up to 350 million people around the world might die.