Fighting to prevent a flu pandemic

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,” Ms Chan, chief of pandemic influenza preparedness at the World Health Organisation (WHO), said.

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

After Severe Acute Respiratory Syndrome (SARS) broke out in the territory in 2003, she also led the fight against the epidemic that took nearly 300 lives.

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

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.

Forecasts predict more than 25 million hospital admissions and up to seven million deaths globally.

Previous pandemics, including the 1918-1919 “Spanish Flu” caused an estimated 40-50 million deaths while the most recent in 1968 claimed between one million and four million lives.

“This is perhaps the only time since 1968, which was the last pandemic, that we are getting signs, symptoms and warnings from nature,” she said.

Only 40 of WHO’s 192 member states have drawn up pandemic preparedness plans.

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

Global supplies of antivirals are inadequate but the deal could slow the spread of an outbreak.

“Antivirals are very useful but they are not a silver bullet,” Ms 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 won’t be enough.

Ms Chan said a “constellation of tools” were required - antivirals, vaccines and public health measures. She dismissed the idea travel warnings - which the WHO issued during the SARS outbreak against China, Hong Kong, Taiwan and Toronto - could halt spread of a flu pandemic because people infected with influenza do not immediately display symptoms.

SARS infected more than 8,000 people worldwide and killed more than 800.