Drug-resistant pandemic (H1N1) 2009, South Korea.

Eleven patients with drug-resistant pandemic (H1N1) 2009 were identified in South Korea during May 2009-January 2010. Virus isolates from all patients had the H275Y mutation in the neuraminidase gene. One isolate had the I117M mutation. Of the 11 patients, 6 were ≥ 59 months of age, and 5 had underlying immunosuppressive conditions.

Fatal cases of 2009 pandemic influenza A (H1N1) in Korea.

The aim of this study was to describe the features of deaths associated with the 2009 pandemic influenza A (H1N1) by 26 November 2009 in Korea. We collected standardized case reports on 115 confirmed deaths through a nationwide enhanced influenza surveillance system. The median age was 61 yr (interquartile range [IQR], 0.2-97 yr) and 58 (50.4%) were females. The case fatality rate was estimated as 16 per 100,000 cases. The age-related mortality rate had a J-shaped curve. Eighty-three patients (72.2%) had at least 1 underlying medical disease. Bacterial co-infections were detected in the blood or sputum specimens from 34 patients. Of the 63 patients who were hospitalized in the intensive care unit (ICU), the median time from symptom onset to hospital admission was 2 days (IQR, 0-22 days), and the median time from hospitalization to ICU admission was 1 day (IQR, 0-17 days). Neuraminidase inhibitors were administered to 100 patients (87.0%), 36% of whom began treatment within 2 days. In conclusion, fatal cases from the 2009 influenza A (H1N1) infection in Korea are mainly aged individuals with underlying disease, and associated with pneumonia, bacterial co-infections, and multi-organ failure.

Clinical characteristics of Korean pediatric patients critically ill with influenza A (H1N1) virus.

BACKGROUND: Novel influenza A (H1N1) virus infection has persisted mainly through person-to-person transmission in schools. However, data on critically ill patients infected with H1N1 are currently limited. This study was conducted to investigate the epidemiological characteristics, clinical features, treatment modalities, and clinical outcomes of pediatric patients critically ill with H1N1 infection. METHODS: Subjects included 30 critically ill pediatric patients reported to the Korea Centers for Disease Control and Prevention (KCDC) between June and November 2009. Data were obtained by medical record review and interviews with primary treating physician. RESULTS: Of the 30 patients, 14 died and 16 were discharged from the hospital with complete recovery. The median patient age was 7 years (range, 2 months to 18 years). Nineteen patients belonged to the high-risk group. Cough was the most common initial symptom, followed by fever. In most patients, serum levels of C-reactive protein and lactate dehydrogenase were elevated. Oseltamivir, an antiviral agent, was administered to 29 patients. The most common causes of death were encephalopathy and myocarditis, with a higher mortality rate in the high-risk group. Platelet counts were significantly lower than normal and serum aspartate aminotransferase levels significantly higher in the non-survivors. CONCLUSIONS: The results of this study suggest that Korean high-risk pediatric patients have an elevated mortality rate following infection with novel influenza A (H1N1) virus. Further studies involving high-risk pediatric patients classified using consistent criteria are needed to confirm our results.

The spread of pandemic H1N1 2009 by age and region and the comparison among monitoring tools.

This report describes the pattern of the spread of the pandemic H1N1 2009 and compares 3 monitoring tools until the 57th week or January 31, 2010. The 1st week was from December 28th, 2008 to January 3rd, 2009. A total of 740,835 patients were reported to be infected with pandemic H1N1 2009 and 225 patients were reported to have died of pandemic H1N1 2009. The number of patients aged from 7 to 12 was the largest (183,363 patients in total) but the virus spread and then was suppressed most quickly among the children between 13 and 18. The region-determinant incidence of patients showed diverse patterns according to regions. The peak of the ILI per thousand was at the 45th week, the number of antiviral prescriptions reached its peak at the 44th week, and the peak based on reported patients was the 46th week. As of February 3 2010, the outbreak passed through the peak and has gradually subsided. Now it is time for the government and the academic world to review this outbreak, efficacy of vaccination, and further preparation and response for the next pandemic.

Identification of enteroviruses by using monoclonal antibodies against a putative common epitope.

A common epitope region of enteroviruses was identified by sequence-independent single-primer amplification (SISPA), followed by immunoscreening of 11 cDNA libraries from two Korean enterovirus isolates (echoviruses 7 and 30) and a coxsackievirus B3 (ATCC-VR 30). The putative common epitope region was localized in the N terminus of VP1 when the displayed recombinant proteins from the phages were chased by the convalescent-phase sera. The genomic region encoding the common epitope region was amplified and then expressed by using the vector pGEX-5X-1. The antigenicity of the expressed recombinant protein was identified by Western blotting with guinea pig antisera for six different serotypes of enteroviruses. After successive immunization of mice with the recombinant common epitope protein, splenocytes were extracted and hybridized with P3X63-Ag8-653 cells. A total of 24 hybridomas that produced monoclonal antibodies (MAbs) against the putative common epitope of enteroviruses were selected. Four of these were immunoglobulin G1 isotypes with a kappa light chain. These MAbs recognized 15 Korean endemic serotypes and prototypes of enteroviruses in an indirect immunofluorescence assay. These results suggest that the expressed protein might be a useful antigen for producing group common antibodies and that the use of the MAbs against the putative common epitope of enteroviruses might be a valuable diagnostic tool for rapidly identifying a broad range of enteroviruses.