WHO's emergency committee is meeting this week to review the status of the H1N1 pandemic. A decision to declare the pandemic over could come then, says Margaret Chan, centre, director general of the World Health Organization. (Laurent Gillieron/Keystone/Associated Press)

The director general of the World Health Organization expects the H1N1 flu pandemic to be officially declared over in the next week or so.

Dr. Margaret Chan said her agency and the experts who advise it are feeling increasingly confident H1N1 is behaving more like a seasonal flu virus than a pandemic one.

"All in all, people feel that the overall picture looks like we are ready to declare post-pandemic globally very soon," Chan said in an interview from Hong Kong.

She said she expects the WHO's emergency committee to convene a meeting this week to review the situation, and the declaration could come then.

There's been little H1N1 activity in the Northern Hemisphere since late last year.

But the WHO said the virus has killed at least 18, 500 people worldwide since it emerged in the spring of 2009.

The WHO has been watching for a number of signs it believes are key to determining that H1N1 is morphing into a seasonal flu virus.

One critical indicator is the timing of flu activity. In the Northern and Southern Hemispheres, flu viruses mainly circulate during winter months. But during pandemics, widespread out-of-season transmission can occur.

The WHO has faced allegations it called the pandemic to pad the pockets of Big Pharma — a charge Chan has fiercely denied.

Instead of excruciating medical dilemmas, this pandemic posed tough communications issues, Chan suggests.