By Stephanie Nebehay

source: http://www.reuters.com/article/swineFlu/idUSTRE5441IX20090505

GENEVA (Reuters) - More than 150 scientific experts will on Tuesday examine and compare notes on the H1N1 flu virus, including its severity and incubation period, the World Health Organization (WHO) said.

The WHO's scientific committee will hold a teleconference from 1400 GMT to try to fill gaps in scientific knowledge about the new strain, which the WHO says has officially infected 1,124 people in 21 countries, with Portugal the latest addition.

"It is important that the scientific committee meet to share information and try to understand the incubation period, severity of disease and also what age groups are affected mostly by the new strain," WHO spokeswoman Fadela Chaib said.

There are no immediate plans to also convene an emergency committee which can recommend changing the pandemic alert level, she told a news briefing in Geneva.

Mexico is considered the epicenter of the outbreak caused by a new combination virus known popularly as "swine flu."

The WHO is keeping a close eye on outbreaks outside North America for signs of sustained human-to-human spread as it tries to decide whether to declare a full-blown pandemic.

TAMIFLU STOCKS BEING DISPATCHED

The United Nations agency also said it would begin sending 2.4 million treatment courses of Tamiflu, an antiviral proven effective against the new flu, on Tuesday to 72 countries deemed in need, including Mexico. [nL5636466]

The Swiss drugmaker Roche Holding AG donated the stockpiles to the WHO several years ago for use in a possible influenza pandemic. Shipments will be made from "three hubs" -- Switzerland, the U.S. state of Maryland, and Dubai in the United Arab Emirates, Chaib said.

WHO's latest tally includes 590 people confirmed as having the new disease in Mexico, 25 of whom died. The United States has reported 286 laboratory-confirmed cases including one death.

Flu infections without fatalities have been confirmed in the following countries: Austria (1), Britain (18), Canada (140), Hong Kong, China region (1), Costa Rica (1), Colombia (1), Denmark (1), El Salvador (2), France (4), Germany (8), Ireland (1), Israel (4), Italy (2), Netherlands (1), New Zealand (6), Portugal (1), South Korea (1), Spain (54) and Switzerland (1).

The WHO toll lags national reports but is considered more scientifically secure, as it reflects sophisticated tests carried out in its global network of laboratories.

It remains unclear when, or whether, the WHO will raise its pandemic alert to the top of its 6-point scale and activate emergency response plans to fight the new virus.

Last week the WHO raised its pandemic alert level from 3 to 4 and then to 5 in recognition of the transmission of the virus in Mexico and among communities in the United States and Canada. The current phase 5 signals that a pandemic is "imminent."

Keiji Fukuda, WHO acting assistant director general, said on Monday that most people infected in Europe and Asia to date had been to Mexico and did not catch the virus in their communities.