WHO chief says world to prepare for severe flu

Countries should be ready for more serious H1N1 flu infections and more deaths from the newly discovered virus, World Health Organisation chief Margaret Chan said yesterday.

The highly contagious strain must be closely monitored in the southern hemisphere, where the winter season is beginning, as it could mix with seasonal influenza and mutate in "unpredictable ways," Ms Chan told the closing session of her UN agency's annual congress.

"In cases where the H1N1 virus is widespread and circulating within the general community, countries must expect to see more cases of severe and fatal infections," she said. "We do not at present expect this to be a sudden and dramatic jump in severe illness and deaths."

According to the WHO's latest tally, the strain has infected more than 11,000 people in 42 countries, and killed 86 of them.

Ms Chan told the final plenary of the week-long World Health Assembly that developing countries need to quickly improve their monitoring for the flu, which has caused mainly mild symptoms in most patients but could become more serious as it spreads.

"This is a subtle, sneaky virus," she said. "We have clues, many clues, but very few firm conclusions."

She also stressed there is little real difference between the WHO's current pandemic alert level of 5 and the highest of 6 in terms of preparedness measures taken, and said she would consult experts before opting to raise it again.

"The decision to declare an influenza pandemic is a responsibility and a duty that I take very, very seriously," she said. "I will consider all the scientific information available. I will be advised by the emergency committee."

Pressure has been growing for Ms Chan to factor in the severity of the newly discovered disease as well as its geographic spread before sounding the pandemic alarm that several governments said could trigger unnecessary panic.

The WHO's guidelines define a pandemic solely on the basis of the pattern of its spread, and not on the symptoms a virus causes. Following those rules, Ms Chan would need to raise the alert level to Phase 6 as soon as H1N1 is shown to be spreading in a sustained way in one country outside of North America.

There are large pockets of infections in Japan, Spain and Britain, which have 294, 113 and 112 cases each, respectively, according to the WHO figures released yesterday.