Possible Recurrent Pandemic (H1N1) 2009 Infection, Israel

The impact of infl uenza epidemics on mortality: introducing a severity index.ing infl uenza epidemics using search engine query data. Flu Trends " data for pandemic H1N1 in-fl uenza: the New Zealand experience. trends: a web-based tool for real-time surveillance of disease outbreaks. To the Editor: We report 2 cases of possible recurrent laboratory-confi rmed infection with pandemic (H1N1) 2009 virus in Israel. Patient 1, a 24-year-old man, had Noonan syndrome (1,2). He was hospitalized on August 10, 2009, because of high-grade fever and cough. At admission, a nasopharyngeal specimen was collected for pandemic (H1N1) 2009 virus real-time reverse transcription–PCR (RT-PCR) (ABI 7500; Applied Bio-systems, Foster City, CA, USA) for the pandemic hemagglutinin gene; a validated in-house protocol developed at Israel Central Virology Laboratory was used, as previously described (3). Briefl y, the in-house assay was validated against the assay for pandemic (H1N1) 2009 virus developed by the Centers for Disease Control and Prevention (CDC; Atlanta, GA, USA). The in-house assay was as sensitive as the CDC assay; however, the in-house primers and probes were more specifi c for detecting pandemic (H1N1) 2009 virus with 105% amplifi cation efficiency of viral RNA that was logarithmically serially diluted. In addition, of 100 samples tested side by side with the in-house and CDC assays, 75 samples were positive by both assays, and 25 were negative by both assays; thus, the sensitivity and specifi city of the in-house assay were 100%. The patient was not treated with neuraminidase inhibitors and did not require supportive treatment; after 1 day of hospitalization, he was discharged with a diagnosis of upper respiratory tract infection. The laboratory subsequently reported the RT-PCR as positive for pandemic (H1N1) 2009 virus. On November 22, the man was hospitalized again for dyspnea and fever. The RT-PCR result from a nasopharyngeal sample collected at admission was positive. Hemaggluti-nation-inhibition assay demonstrated a high titer (320) of serum antibody against pandemic (H1N1) 2009 virus in a blood sample taken at admission. The patient took oseltamivir for 5 days, and his condition markedly improved. Result of a repeat RT-PCR at discharge was negative. An identical neuraminidase gene sequence was detected during both illness episodes (August and Novem-ber). The specimens were also tested with an experimental RT-PCR assay for rapid detection of the oseltamivir resistance mutation H275Y on the pandemic neuraminidase gene (4). For specimens collected during both episodes, the virus was oseltamivir sensitive. Patient 2, …