GENEVA: More than 150 scientific experts yesterday were examining and comparing notes on the H1N1 flu virus, including its severity and incubation period, the World Health Organisation (WHO) said.

The WHO's scientific committee was scheduled to hold a teleconference from 1400 GMT (10 pm Beijing time yesterday) 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.