International efforts have pushed back the spread of bird flu this year, but the risk of a global influenza pandemic killing millions is as great as ever, the United Nations and World Bank reported on Tuesday.

Most countries now have plans to combat a pandemic, but many of the plans are defective, said the report, issued ahead of a bird flu conference due to be attended by ministers from some 60 countries in Sharm el-Sheikh, Egypt, from October 24-26.

The report, fourth in a series since a bird flu scare swept the globe three years ago, followed a new World Bank estimate that a severe flu pandemic could cost $3 trillion and result in a drop of nearly 5 percent in world gross domestic product.

The highly pathogenic H5N1 bird flu virus is endemic in poultry in parts of Asia, but experts fear it will mutate into a form that is easily passed from human to human, sparking a pandemic similar to three others in the past century.

The U.N.-World Bank report said that in the first nine months of this year no countries were newly infected with highly pathogenic bird flu, compared with four in the first half of 2007. Just 20 countries had experienced outbreaks so far this year, compared with 25 last year.

Since late 2003 there have been 387 cases of humans catching the disease from birds, of whom 245 have died in Asia, Africa and Europe. But of these there have been only 36 human cases this year, of which 28 proved fatal.

"This particular virus, H5N1, is a much milder threat now than it was in September 2005," U.N. influenza coordinator David Nabarro told a news conference.

PANDEMIC THREAT UNCHANGED

But the report said H5N1 was still "actively circulating among poultry in a number of hotspots" and was entrenched in Indonesia and Egypt. It called for continued vigilance and investment worldwide to combat the disease, saying, "The threat of an influenza pandemic remains unchanged."

Nearly all the 148 countries that provided data for the report have contingency plans in place to deal with a pandemic, the authors said.

But many plans were "not legally or logistically feasible" and lessons from simulations had not been drawn on to revise plans, they said. Authorities in rich countries were better prepared than in poor countries, they added.

"We worry that many of those plans have still not been adequately tested to see whether or not they will be valid when the pandemic actually starts," Nabarro said.

"It's not enough just to have written a plan and have everybody signing off on it, you also have to check it, test it and make sure that it works."

Nabarro also said while the focus had been on H5N1, "any influenza virus could cause a pandemic and we just can't say for certain when the next pandemic will come."

The World Bank has estimated that more than 70 million people could die worldwide in a severe pandemic. According to a Stanford University Web site, some 20-40 million people died in the so-called Spanish Flu influenza pandemic in 1918-1919.

In its latest study, a September update of a report first published two years ago, the World Bank raised the cost of such a pandemic from $1.5-$2 trillion to more than $3 trillion and said world GDP could drop by 4.8 percent.