* WHO probing drug resistant swine flu in immune-suppressed
* Cases reported in Britain, US may mean they at higher risk
(recasts, adding U.S. report on cases and WHO quote)
By Stephanie Nebehay
GENEVA, Nov 24 The World Health Organisation is
looking into reports in Britain and the United States that the
H1N1 flu may have developed resistance to Tamiflu in people with
severely suppressed immune systems, a spokesman said on Tuesday.
Britain's Health Protection Agency (HPA) said five cases
have been confirmed in Wales of patients infected with H1N1
resistant to oseltamivir -- the generic name of Roche ROG.VX
and Gilead Sciences Inc's (GILD.O) antiviral drug Tamiflu.
The patients had serious conditions that suppressed their
immune systems, which can give the virus a better than usual
opportunity to develop resistance, the HPA said. It said the
drug-resistant strain had probably spread person to person.
"We have seen the reports, we need to look into them," WHO
spokesman Thomas Abraham said in Geneva.
The U.S. Centers for Disease Control and Prevention last
week also reported four cases of H1N1 resistant to Tamiflu at
Duke University Hospital in North Carolina. All were said to be
very ill with underlying severely compromised immune systems and
multiple other complex medical conditions. [ID:nN20243634]
The WHO spokesman said both the reports involved Tamiflu
resistance in people with severely compromised immune systems.
"We'll see if we need to put any additional measures in
place to protect this vulnerable group of patients. It might
mean that they are at more serious risk than others," Abraham
People with suppressed immune systems, such as those
undergoing chemotherapy or suffering from HIV are more likely to
fall ill from infections.
The WHO has previously reported cases of the pandemic virus
being resistant to oseltamivir but says these are rare.
Abraham, asked whether the cases in Wales would be the first
instance of person-to-person transmission of a Tamiflu-resistant
form, replied: "As far as I know there have been possibilities
but it never has been conclusively shown."
H1N1, a mixture of swine, bird and human viruses, has killed
at least 6,770 people globally, according to the WHO. Most
people suffer mild symptoms such as aches or fever, but recover
without special treatment, it says.
Separately, the WHO said it was still probing whether a
mutation in the H1N1 influenza strain, detected most recently in
Norway last week, is causing the severest symptoms among those
The Norwegian Institute of Public Health said last Friday
the mutation could affect the virus' ability to go deeper into
the respiratory system, causing more serious illness.
"It is a major issue we are looking at," Abraham said.
"If the mutation in fact is associated with severe cases
then we really need to know about it. This might be a signal. We
need to investigate," he said. "As of now there is no evidence
of a particular association with severe cases."
So far, antiviral drugs and vaccines have been effective
against the mutated form, he said.
There have now been four cases of mutated virus in patients
in Norway, following a similar mutation in H1N1 viruses
circulating in several other countries since April, he said.
The other countries are Brazil, China, Japan, Mexico,
Ukraine and the United States.
"What we've seen has been pretty much equal in terms of
severe and non-severe cases," Abraham said.
(Editing by Jonathan Lynn)
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