Doubts over bird flu drug

Virus develops resistance to Tamiflu

Sarah Boseley

London: Serious questions were raised on Thursday about the ability to combat an anticipated bird flu pandemic following the deaths of two persons who were being treated with the drug the world is stockpiling as a safeguard against the virus.

To the dismay of medical experts and concern among those responsible for the worldwide efforts to fight a pandemic, the H5N1 bird flu virus in the bloodstream of the two patients in Vietnam rapidly developed resistance to the drug, Tamiflu.

One of them, a 13 year-old girl, appeared to be stable at first and then rapidly worsened as the virus mutated, became more aggressive and eventually killed her.

The deaths are reported in the respected New England Journal of Medicine by doctors funded by the British Wellcome Trust working in Vietnam. They urge changes to the global plans for fighting a flu pandemic. Other antiviral drugs are needed alongside Tamiflu, they say.

An eminent professor at Cornell University in New York calls the report ``frightening'' in a commentary in the journal. Anne Moscona, from the department of paediatrics, microbiology and immunology at Weill medical college, says Tamiflu-resistant H5N1 ``is now a reality'' and calls for efforts to prevent individuals stockpiling the drug.

Its misuse, she says — by people who, for instance, take too low a dose — will breed resistance and further undermine its effectiveness if a pandemic sweeps the world.

Demand for Tamiflu, however, remains so strong the drug's manufacturer, Roche, cannot keep up with orders, as most countries attempt to stockpile. Alan Hay, who heads the WHO Influenza Centre of the U.K.'s National Institute of Medical Research, said it was important to remember that four of the eight Vietnamese patients in the study survived after their treatment with Tamiflu. But, he said, the report was of ``very significant concern in regard to how we use these drugs to treat people.''

It had already been recognised that resistance could build against Tamiflu. In Japan, 16 per cent to 18 per cent of children treated with the drug for ordinary forms of flu developed resistance. It appeared, he said, that resistance was more likely in children because they had not been exposed to the prevailing strains of flu.

- Guardian Newspapers Limited 2005

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