Wednesday, December 2, 2009

Patients in Md., Va. treated for Tamiflu-resistant swine flu

Washington Post Staff Writer
Wednesday, December 2, 2009; 3:55 PM

Two swine flu patients in Maryland and one in Virginia were hospitalized with a form of the virus resistant to a commonly used medicine, prompting infectious disease specialists to call for renewed caution even as the intensity of the pandemic nationwide has declined.

Tamiflu is one of the key drugs used on the sickest patients, and the number of cases where it can no longer kill the H1N1 virus is tiny. But epidemiologists say experience with other flu strains shows that resistance can take over quickly, making monitoring and prevention crucial.

"I don't want to scare the public, but I do want people to be responsible in what they need to be doing, not only for their patients but also for public health," said Trish Perl, a professor at Johns Hopkins University Hospital.

"It's been reported in Seattle, it's been reported at Duke, it's been reported in our place. All of the sudden we're starting to see . . . more resistance than we saw earlier this spring," she said. "What it calls for is increased vigilance."

Diane Helentjaris, head of Virginia's office of H1N1 response, said two state residents have been treated for Tamiflu-resistant swine flu, one at a hospital in Virginia and one in another state.

"It's not unexpected at all, when you have many, many people taking an antiviral medication," she said. Extended treatment for those with immune problems is another issue. "The longer you're on something the more likely you might develop some resistance," she said.

Both Hopkins patients had weakened immune systems and were being treated under protocols consistent with leukemia patients. Staff had been vaccinated and wore masks, hospital officials said. Perl said initial virus samples responded to Tamiflu, but that changed during the onslaught of the treatment itself, leading to a mutated, resistant form. "Under the pressure it can emerge," she said. Doctors can try a different drug in such cases. Both patients were eventually discharged.

Perl said Tamiflu should not be over-prescribed, because that can lead to more chances for mutations. And people should avoid complacency and get vaccinated, she said.

In the District, officials confirmed the city's first swine flu-related death, of an adult male with a preexisting medical condition, Health Department spokeswoman Dena Iverson said.

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