Oseltamivir-Resistant Pandemic H1N1 2009 Virus Emerging

Immunosuppressed patients at particular risk for oseltamivir-resistant pandemic H1N1 2009 virus

WEDNESDAY, Aug. 3 (HealthDay News) -- Clinicians should be aware of an emergence of oseltamivir-resistant pandemic H1N1 2009 virus, particularly in immunocompromised patients, according to a study published online July 29 in the U.S. Centers for Disease Control and Prevention's Emerging Infectious Diseases.

Laurence Calatayud, from the Health Protection Agency in London, and colleagues investigated risk factors for severe infection and the emergence of oseltamivir resistance in patients with oseltamivir-resistant pandemic H1N1 2009 virus infections. Patients had confirmed oseltamivir-sensitive pandemic H1N1 2009 virus infections (control group) or confirmed oseltamivir-resistant infections (case patients). They were hospitalized between January 2009 and April 2010 in England or Scotland.

The investigators found that 21 of the 28 case patients with available information were immunocompromised, and 31 of 33 case patients had been given antiviral drugs before a sample was taken. Case patients were significantly more likely than controls to be immunocompromised and had an increased risk for developing respiratory complications, after adjusting for confounders.

"Clinicians should be aware of the emergence of oseltamivir-resistant pandemic (H1N1) 2009 virus, particularly in immunosuppressed patients. Testing for antiviral resistance is needed, particularly among this group, to ensure appropriate antiviral prescribing, minimize the risk for treatment failure, and minimize the risk of person-to-person transmission of a resistant strain," the authors write.

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