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Tamiflu cut illness in swine flu

Patients taking oseltamivir had less fever, pneumonia and viral shedding

Louise Prime

Wednesday, 29 September 2010

Oseltamivir (Tamiflu) reduced the likelihood of developing pneumonia in previously healthy people with mild pandemic 2009 influenza A(H1N1) virus infection, research from China has shown. The retrospective study, published on bmj.com today, showed that the drug also appeared to reduce the duration of both fever and viral RNA shedding with swine flu.

People appeared to have been protected by oseltamivir from radiographically-confirmed pneumonia when medical charts were reviewed opportunistically, but the authors acknowledge limitations of their study and warn that their results should be interpreted with caution.

Researchers examined the medical records of 1291 children and adults in China who had been laboratory-confirmed cases of H1N1 flu in the 2009 pandemic, aiming to assess the benefit – if any – to healthy people of taking oseltamivir for swine flu. The antiviral had already been shown to reduce the severity and duration of symptoms, and perhaps also the likelihood of developing complications, in previously healthy people with seasonal influenza.

Patients were, on the whole young – median age 20 years – and more than three-quarters of them had taken oseltamivir. They started the drug at, on average, three days from the onset of symptoms. Almost three-quarters (71%) of all patients had had a chest X-ray, which in 12% indicated pneumonia. None were admitted to intensive care or needed mechanical ventilation.

Even in patients who started oseltamivir more than two days after symptom onset, it offered significant protection from developing radiologically confirmed pneumonia. In patients who started the drug within two days, it also reduced their duration of both fever and viral RNA shedding. These effects were independent of age, sex, influenza vaccination status and antibiotic treatment.

The researchers said their results might also indicate that viral shedding continues for longer with swine flu than with seasonal flu; it lasted 21 days in two previously healthy young men.

The authors conclude: “Treatment with oseltamivir was associated with a significantly reduced development of radiographically confirmed pneumonia and a shorter duration of fever and viral RNA shedding.

“Though these patients benefited from treatment, the findings should be interpreted with caution as the study was retrospective and not all patients underwent chest radiography.”

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