Margaret Chan, responsible for helping defend the world against an influenza pandemic that could kill millions, says an outbreak of bird flu among humans may be imminent, but there is still time to act.

“We have a window of opportunity to prevent a pandemic or at least delay the spread of a pandemic,” said Chan, chief of pandemic influenza preparedness at the World Health Organization (WHO).

The H5N1 bird flu virus, which returned late last year, has killed 63 in Asia, mainly in Vietnam and Thailand. It has also struck flocks in six Russian regions and Kazakhstan.

So far there has been no sustained human-to-human transmission, according to the WHO, a United Nations agency.

But from experience, Chan, 58, knows that it is important to act quickly. As head of Hong Kong’s health department in 1997, when bird flu made the first jump to humans, she within days ordered the entire poultry population of 1.5 million birds slaughtered.

After severe acute respiratory syndrome (SARS) broke out in the tiny territory in 2003, she also led the fight - but was among top officials who later came under fire in a legislative inquiry on handling of its epidemic that took nearly 300 lives.

Her warning now comes as avian flu has spread across Asia and to Europe’s doorstep.

“Buying time will allow us to fast-track pandemic vaccine production. It will allow governments to put in place a host of emergency public health measures that will reduce mortality and morbidity, and social and economic disruption,” Chan said in an interview.

But WHO and other experts fear the bird flu virus will mutate or mix its genetic material with seasonal human flu - which kills up to 500,000 people a year - creating a deadly pandemic strain that could spread rapidly across continents.

The diminutive doctor, who began her career as a teacher before earning a medical degree in Ontario, Canada, is working hard to convince all governments to ramp up their defenses.

Forecasts predict more than 25 million hospital admissions and up to 7 million deaths globally within a short period.

Previous pandemics, including the 1918-1919 “Spanish Flu” which caused an estimated 40 million-50 million deaths, and the most recent in 1968, which claimed between 1 million and 4 million lives, took the world by surprise, according to Chan.

MORE SIGNS

“This is perhaps the only time since 1968, which was the last pandemic, that we are getting signs, symptoms and warnings from nature… More and more birds are dying in different parts of the world - this is the kind of signals and early warnings that we are referring to,” she told reporters in late July.

Urgently preparing for an outbreak should save lives.

But only 40 of WHO’s 192 member states have drawn up pandemic preparedness plans, with varying degrees of scope.

Chan called for countries to “put a life to these plans,” by carrying out simulation and desk-top exercises.

“People who have gone through this process understand how important it is. It helps you to identify areas of good preparedness, highlights gaps and to bring to the attention of people in charge how to refine plans,” she said.

She realizes the exercise may be painful for some governments but is dedicated to the cause. “I have a lot of passion for global public health - that is where I am coming from,” Chan said.

“One has to be very vigilant, honest and brave. Sometimes you need to make unpopular, difficult recommendations to political leaders which may have a short-term impact on the economy and on certain sectors,” she added.

NO SILVER BULLET

The WHO has begun to build a first line of defense against the pandemic, securing a donation by Swiss drug maker Roche of enough Tamiflu antiviral drug to treat 3 million people.

Global supplies of antivirals are deemed inadequate but the deal, clinched in August, could slow the spread of an outbreak in poor countries that can’t afford their own stockpiles.

“Antivirals are very useful but they are not a silver bullet. It doesn’t solve all your problems,” Chan said.

Vaccines are the “best intervention” but exactly which virus will emerge as the pandemic strain is not known yet. And global manufacturing capacity, 300 million doses, won’t be enough.

Chan said that a “constellation of tools” were required - antivirals, vaccines and effective public health measures - including quarantines and protective clothing such as masks.

Any “unnecessary contact of people” should be kept to a minimum in an outbreak, which may require school closures.

But Chan dismissed the idea that travel warnings - which the WHO issued during the SARS outbreak against China, Hong Kong, Taiwan and Toronto - could halt spread of a flu pandemic.

This was because people infected with influenza do not immediately display symptoms.

China was widely blamed for concealing the initial scale of the SARS contagion, which eventually infected more than 8,000 people worldwide and killed more than 800.

Chan, asked whether secretive or authoritarian regimes were open to cooperation ahead of a pandemic, replied: “Countries have improved since SARS. They understand the importance of responding and being as prompt and transparent as possible.”

“The lesson I learned from previous outbreaks is a local public health issue can become an international issue because of the volume of travel in terms of people, goods and services,” she said.