Friday, April 28, 2006

No stopping bird flu, studies conclude

Associated Press

Washington — If pandemic influenza hits in the next year or so, the few weapons the United States has to keep it from spreading will do little, a new computer model shows.

A pandemic flu is likely to strike one in three people if nothing is done, according to the results of computer simulation published in Thursday's journal Nature. If the U.S. government acts fast enough and has enough anti-viral medicine for preventive dosings — which the United States does not — that could drop to about 28 per cent of the population getting sick, the study found.

“Both cases we came up with were very pessimistic,” said lead author Neil Ferguson of the Department of Infectious Disease Epidemiology at Imperial College in London. “There is no single magic bullet for stopping pandemic flu.”

So far this year, H5N1 bird flu — which is not yet pandemic because it doesn't move easily between humans — has infected 204 people and killed 113, according to the World Health Organization. Most of the human cases and deaths have been in Asia, but birds with the disease have been found in Europe.

Dr. Ferguson's computer simulation is the second released this month and is more pessimistic than one led by Timothy Germann of Los Alamos National Laboratory, who said the flu could be less infectious and that efforts could slow it a bit.

Measures such as closing schools to halt breeding grounds and the use of the anti-viral Tamiflu could reduce the disease's toll, Dr. Ferguson said. But efforts to stop flu from entering American borders — usually on planes with sick passengers — won't work, he said, adding that at most they can buy a couple of weeks' delay before the disease sets in.

If a country gets enough Tamiflu for half its population, it could then act aggressively in dosing families of flu-struck patients and that could cut the flu-attack rate by 75 per cent, Dr. Ferguson said.

But even Dr. Germann, who conducted the more optimistic study, said no one knows which computer model is closer to reality.

“It would have to be a very weak pandemic strain for us to be able to stop it right now,” Dr. Germann said this week. “Most likely we wouldn't be completely prepared.”