GENEVA (Reuters) - The first H1N1 infection found to be resistant to
the antiviral drug Tamiflu represents an isolated case with no current
implications for public health, the World Health Organization (WHO)
said on Tuesday.

The United Nations agency has declared a global pandemic is underway
from the virus known as swine flu which has so far been treatable with
Tamiflu, made by Roche.

WHO spokesman Dick Thompson said that the discovery of a patient in
Denmark whose infection did not respond to the drug, revealed by the
Swiss company and Danish officials on Monday, did not amplify the
severity of the virus.

"This is an isolated case. At this time, there is no public health
implication. But we must remain alert as the virus can change at any
time and we must not be complacent," he told Reuters.

Officials say the patient is now well and no further contagion with the resistant virus was detected.

Resistance to Tamiflu has been previously documented in the deadly bird flu virus H5N1 and seasonal H1N1 flu, Thompson said.

"We need to monitor the virus (H1N1) continuously," he said, adding
that the WHO's global influenza surveillance network linking
laboratories in 97 countries would keep monitoring it.

"WHO is not changing its recommendations for the use of antivirals,"
Thompson added, referring to the global body's advice to its 193 member
states.

The WHO has previously said that the H1N1 virus is sensitive to a
class of antiviral drugs which includes Tamiflu, known generically as
oseltamivir, and Relenza by GlaxoSmithKline, known generically as
zanamivir.

Denmark's State Serum Institute said, when making the announcement
on Monday, that it was expected that the strain would at some point
show resistance to Tamiflu.

It said that while the patient was found to be infected with a virus
strain that had mutated to a form resistant to Tamiflu, the alternative
drug Relenza, which is inhaled, remained an effective treatment.

GLOBAL PANDEMIC

The WHO on June 11 raised its pandemic flu alert to its highest
level of 6, signifying that the first influenza pandemic since 1968 was
under way [ID:nLC321991]

Flu viruses mutate regularly and can develop resistance to drugs at any time.

The WHO has said Tamiflu was working against strains of the new H1N1
flu but some health experts have expressed concern that it might be
less effective than Relenza, since there have been widespread reports
in the past year of resistance to Tamiflu by seasonal H1N1 flu, a
distant cousin of the new swine flu virus.  Continued...