The World Health Organization Chief, Margaret Chan, has renewed warnings over the A/H1-N1 threat. She cautioned listeners at the annual World Health Assembly, which is being held in Geneva.

The two items topped the agenda at this year's World Health Assembly, amid concerns that the virus is continuing to spread around the globe.

The WHO chief acknowledged the virus mainly causes a mild illness, with few deaths outside the outbreak in Mexico.

But she warned that the behavior of a flu virus is unpredictable.

Margaret Chan, WHO Director-General, said, "We remain in phase five today. This virus may have given us a grace period, but we do not know how long this grace period will last. No one can say, no one can say whether this is just the calm before the storm."

Margaret Chan noted that the virus has now spread to the Southern Hemisphere after breaking out in North America.

There is a risk that it could combine with other flu strains circulating now among humans south of the equator.

Another concern is that the A/H1-N1 flu might combine with the bird flu virus that has been circulating for several years.

Margaret Chan, WHO Director-General, said, "We have lived for five long years under the threat of pandemic caused by the lethal H5N1 avian influenza virus. This has left our world better prepared, but also very scared."

A defining feature of a pandemic is that the world's population is susceptible to infection.

Not all will contract the illness, but nearly all are at risk.

Margaret Chan pointed out the manufacturing capacity for antiviral drugs and flu vaccines is not enough for a world with 6.8-billion inhabitants.

Countries will likely be advised to target their disease control efforts and resources to high-risk groups, including those with underlying health conditions.

(CCTV May 19, 2009)