WHO: Swine flu outbreak has not yet peaked

The World Health Organization announced Wednesday that it was too early to declare that the H1N1 pandemic had peaked and urged nations around the world to remain vigilant.

Although the spread of the virus had slowed or was declining in many parts of the world, including the United States and Western Europe, experts remain concerned because the virus had started to spread in parts of West Africa and winter is still to come in the Southern Hemisphere, the agency said.

The decision was based on the recommendations of a 15-member emergency committee that met for two hours Tuesday to assess the situation.

"The committee advised that it was premature to conclude that all parts of the world have experienced peak transmission of the H1N1 pandemic influenza and that additional time and information was needed to provide expert advice on the status of the pandemic", WHO Director-General Margaret Chan said in a statement. "The committee accordingly suggested that the committee be re-convened in a few weeks."

In the meantime, the WHO will continue its highest pandemic alert, although it will modify its advice to countries that they "maintain" instead of "intensify" surveillance of the virus.

During a briefing for reporters on Wednesday, Keiji Fukuda, the WHO's top flu expert, said the WHO had confirmed that the virus was spreading for the first time in Senegal and Mauritania, and was investigating the situation in other parts of West Africa.

Fukuda urged continued vigilance to prevent the spread of the virus, even though it has not been as lethal as past pandemics.

"It appears to be on the less severe side of the spectrum of pandemics that we have seen in the 20th century", Fukuda said.

The WHO has confirmed 16,226 deaths attributable to the H1N1 pandemic virus, but the actual death toll is expected to be much higher because the flu strain has so far not been diagnosed in many cases, he said.