Global Assessment of Resistance to Neuraminidase Inhibitors, 2008-2011: The Influenza Resistance Information Study (IRIS)

RJ Whitley, Charles Boucher, B Lina, JS Nguyen-Van-Tam, Ab Osterhaus, M (Martin) Schutten, AS Monto

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Abstract

Background. Following emergence of naturally occurring oseltamivir-resistant influenza A(H1N1) viruses, a global observational investigation, the Influenza Resistance Information Study (IRIS; NCT00884117), was initiated in 2008 to study neuraminidase inhibitor (NAI) resistance and clinical outcome. Methods. Patients with influenza-like illness and/or positive rapid test results agreed to swabs of the posterior nares that were assessed by semiquantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) for influenza type and subtype and NAI resistance. RT-qPCR-positive specimens were cultured, sequenced, and phenotypically tested for NAI resistance. Treatment was at the physician's discretion. Results. Of 1799 influenza-positive (RT-qPCR) patients, 1281 had influenza A (47 seasonal H1N1; 335 H3N2; 899 H1N1pdm2009) and 518 had influenza B. Antivirals were administered to 1041 (58%) patients (26, 245, 514, and 256, respectively). All seasonal H1N1 strains were genotypically (H275Y) and phenotypically resistant to oseltamivir. No genotypic resistance was detected in the day 1 samples of any other viral subtypes. Mutation- specific (MS) RT-PCR detected resistance to oseltamivir in 19 pati Conclusions. In years 1-3 of IRIS, emergent resistance to oseltamivir in influenza viruses during treatment was uncommon (2.2%) and mostly found in patients aged 1-5 years. Viral loads were low in many cases and viral clearance rapid.
Original languageUndefined/Unknown
Pages (from-to)1197-1205
Number of pages9
JournalClinical Infectious Diseases
Volume56
Issue number9
DOIs
Publication statusPublished - 2013

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  • EMC MM-04-27-01

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