Possible transmission of pandemic (HIN1) 2009 virus with oseltamivir resistance [letter]

DOI: 10.3201/eid1605.091835
Suggested citation for this article: Mandelboim M, Hindyieh M, Segman-Meningher T, Mendelson E. Possible transmission of pandemic (HIN1) 2009 virus with oseltamivir resistance [letter]. Emerg Infect Dis. 2010 May; [Epub ahead of print]

Possible Transmission of Pandemic (HIN1) 2009 Virus with Oseltamivir Resistance
To the Editor: In March 2009, a new strain of influenza A (H1N1) virus of swine origin emerged; the virus had crossed the species barrier to humans and acquired the capability of human-to-human transmission. Soon after, the World Health Organization raised the worldwide pandemic alert to level 6 (www.who.int/en), declaring the first influenza pandemic in the past 42 years. The virus was named influenza A pandemic (H1N1) 2009 virus. The illness caused by this virus is particularly dangerous for pregnant women and for patients with chronic diseases (1). The preferred treatment is a neuraminidase inhibitor, zanamivir or oseltamivir (2).

Around the world, several dozen cases of resistance to oseltamivir in persons with or without exposure to the drug have been reported (3). However, only limited information is available with regard to initial infections with oseltamivir-resistant viruses (4). We report a case of possible human-to-human transmission of pandemic (H1N1) 2009 virus in Israel.

After the recent discovery of oseltamivir-resistant strains, we conducted a retrospective study of oseltamivir-resistance mutations in viral RNA amplified from specimens from patients hospitalized >1 week with pandemic (H1N1) 2009. All samples were first tested for the H275Y mutation by using an in-house real-time reverse transcription–PCR (RT-PCR) assay developed at the Central Virology Laboratory of Chaim Sheba Medical Center; positive results were confirmed by sequencing. The histidine-to-tyrosine mutation at the 275 position of the neuraminidase protein results in reduced binding of oseltamivir.

During June–August 2009, ≈80 children in an institution for disabled children were suspected of being infected with pandemic (H1N1) 2009 virus. The children had influenza-like signs and symptoms, and at that time the only influenza virus circulating in Israel was pandemic...

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