Resistance to Bird Flu Drug Reported

Tamiflu May Have Failed to Stop Bird Flu in Vietnamese Children

From the WebMD Archives

Dec. 21, 2005 -- Experts have had high hopes that the flu drug Tamiflu would also help fight bird flu, but a new report may temper some of this enthusiasm.

Two children in Vietnam who died of bird flu had developed resistance to the flu drug Tamiflu. A new report detailing the events surrounding the children's deaths is published in The New England Journal of Medicine.

These were the first reported cases of resistance to the drug in bird flu patients, and drug resistance was suspected of contributing to the death of at least one of the children.

Infectious disease specialist Anne Moscona, MD, of Cornell University says the development illustrates the need for governments, public health organizations, and researchers to redouble efforts to develop new drugs, vaccines, and public health strategies to deal with a possible bird flu pandemic.

"I think this is a real warning, but I also feel strongly that this scary turn of events should be taken as an opportunity to do what needs to be done to organize for protecting people against influenza," she tells WebMD.

Early Treatment Didn't Help

One of the victims was a 13-year-old girl who died in January of this year. Her case was especially alarming, Moscona says, because she began treatment with a full dose of Tamiflu within a day of developing flu symptoms.

She initially got better following the initiation of treatment, but her symptoms quickly returned and she died less than a week later.

Moscona says the case suggests that bird flu patients may need higher doses and longer courses of Tamiflu treatment than given to patients with regular flu.

"The most important lesson that I am taking away from this is that we really need to carefully strategize how we are going to use this drug and (similar drugs) in a pandemic situation," she says.

The Case Against Stockpiling

Reports of growing resistance to Tamiflu among people treated for the regular influenza strengthen the argument against personal stockpiling of the drug for use in the event of a pandemic bird flu outbreak, Moscona writes in an editorial.

Continued

In two recent studies from Japan, 16% and 18% of children with the regular flu were reported to be resistant to Tamiflu.

The high rate of acquired resistance is believed to be due to the fact that young children in Japan are typically given very low doses of the drug, which may be insufficient for getting rid of the flu virus.

"Personal stockpiling of [Tamiflu] is likely to lead to the use of insufficient doses or inadequate courses of therapy," Moscona writes. "Shortages during a pandemic would inspire sharing of personal supplies, resulting in inadequate treatment."

She added that undertreatment is a particular concern with regard to children, since they tend to be more contagious than adults and remain contagious for longer periods.

"The habit of stopping treatment prematurely when symptoms resolve (a well-established tendency with antibiotic therapy) could also lead to suboptimal treatment of influenza and promote the development of drug resistance," she writes.

Prescribing on Demand

It is not clear how much personal stockpiling of the antiviral drug has occurred. A few leading public health groups, including the Infectious Diseases Society of America, have called on doctors to resist patient requests for prescriptions to be used for this purpose.

But medical ethicist Allan S. Brett, MD, tells WebMD that stronger guidelines are clearly needed from public health officials who have so far been silent on the issue.

The University of South Carolina professor of medicine says doctors would welcome specific directives from the CDC and state departments of health, just as they welcomed them in the fall of 2004 when there was a shortage of flu vaccine.

"It seems to me that individual practicing physicians should not be put in the middle of something that obviously has so many public health implications," he says.

WebMD Health News

Sources

SOURCES: de Jong, M.D. The New England Journal of Medicine, Dec. 22, 2005; vol 353: pp 2667-2673. Anne Moscona, MD, professor of pediatrics, microbiology and immunology, Weill Medical College, Cornell University, New York City. Allan S. Brett, MD, professor of internal medicine, University of South Carolina, Columbia. WebMD Medical News: "Key Flu Drug May Fail in Super-Flu Outbreak."
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