Tamiflu could make avian flu pandemic worse

The only drug available against a threatened pandemic of avian flu may be useless for many of those infected and could make the pandemic worse, say scientists.

The warning came after a study of 13 Vietnamese patients infected with avian flu and treated with the anti-viral drug Tamiflu found two developed a resistant virus which contributed to their deaths.

Seven of the 13 patients died.

The New England Journal of Medicine, which publishes the findings today, describes them as "frightening". Governments are stockpiling Tamiflu to be used as the first line of defence against a pandemic.

But indiscriminate use of the drug in the event of a pandemic could fuel the growth of a resistant virus, triggering a second wave of infection against which there would be no defence, researchers say.

Sir John Skehel, director of the National Institute for Medical Research, London, and one of the world's leading virologists, said: "That is the great worry. The fear is that all the virus that comes here [to Britain] might be resistant."

Sir John said Tamiflu was better at preventing infection with flu than treating it.

"It's a prophylactic, not a therapeutic. If you give it before the infection develops it is a good drug but if you give it after symptoms appear it has declining value."

He urged the Government to broaden Britain's defence against a pandemic.

Relenza, a drug which works in a similar way to Tamiflu, has not shown signs of triggering resistance but Governments have ignored it because it is harder to take.

"We should be stockpiling other drugs. Some of these mutations are only resistant to Tamiflu. But I am not aware how much Relenza is available," Sir John said.

The H5N1 virus has infected 138 people in the Far East and killed 71, but the fear is it could mutate to become transmissible among humans and spread around the world.

In the Vietnamese study, one of the patients, a 13-year-old girl whose mother had died of avian flu, was treated within 24 hours of developing a cough and fever with a high dose of Tamiflu when "the greatest clinical benefit could have been expected".

But although her condition improved at first, it later worsened and she died eight days after starting treatment. Resistant virus was isolated and at the time of her death the amount of virus in her throat had increased.

"These observations suggest that the development of drug resistance contributed to the failure of therapy and, ultimately, the death of this patient," the authors from the Hospital for Tropical Diseases in Ho Chi Minh City report.

The second patient died after 14 days of illness, also showing signs of an increase in the amount of virus.

- INDEPENDENT