Tamiflu-resistant H1N1 flu does not appear to be spreading in a sustained or worrisome way, a World Health Organisation official said on Tuesday.

“At this point we are not recommending any clinical changes to the approach in treating patients,” WHO Acting Assistant Director-General Keiji Fukuda said, responding to the discovery of drug-resistant H1N1 viruses in three people.

“Right now these examples of oseltamivir resistance remain sporadic cases. We do not see any evidence of widespread movement of oseltamivir resistant viruses,” he told a briefing, using the generic name for Tamiflu, an anti-viral tablet made by Roche and Gilead Sciences.

The three people whose H1N1 virus samples did not respond to Tamiflu - in Denmark, Japan and Hong Kong - have recovered completely from their infection, Fukuda said. He described the Tamiflu-resistant viruses as mutations and not a reassortment or combination with other influenza strains.

So far all discovered Tamiflu-resistant viruses have been sensitive to treatment with the other anti-viral recommended by the WHO, the inhaled drug Relenza made by GlaxoSmithKline under license from Biota, according to Fukuda.

Relenza is known generically as zanamivir.

The WHO, a Geneva-based United Nations agency, raised its global flu alert to the highest level on June 11, declaring the first influenza pandemic since 1968 was underway.

While the H1N1 virus has caused mild flu symptoms in most people, 440 people have died from it and health experts are keeping close watch in case it changes into a more serious form and stops being treatable with existing drugs.

WHO Director-General Margaret Chan has said that patients with mild symptoms may not need any medicines to recover, and that hospital visits are not necessary unless those infected with flu have certain warning signs.

These include long-lasting high fever in adults and a lack of alertness in children. Pregnant women and people with health problems including diabetes have also been identified as vulnerable to more severe effects from the new flu strain.

Last month, Chan also said that the H1N1 virus was stable and there were no signs yet it had mixed with other influenza viruses such as the deadly H5N1 bird flu strain.

Signs of mutations in the H1N1 virus are also critically important to vaccine makers who are trying to develop formulas to match the strain that is now spreading around the world, most commonly known as swine flu.

——
* WHO says Tamiflu-resistant cases sporadic, not spreading

* Not changing recommendations about H1N1 patient treatment

By Laura MacInnis and Stephanie Nebehay

GENEVA (Reuters)