Clinical and Laboratory Findings of the 2012 Winter Seasonal Influenza A and B Outbreak at a Single Institution / 소아감염

PURPOSE: The aim for this study was to investigate clinical manifestation of seasonal influenza A and B during the 2012 winter season in Wonju, South Korea. Their clinical and laboratorial characteristics and effect of oseltamivir were compared and analyzed. METHODS: Children under the age of 18 years who visited the Wonju Severance Christian Hospital with fever or acute respiratory symptoms and who were diagnosed with influenza A or B by rapid antigen test from nasopharyngeal swab were selected for the study. The medical records of patients were retrospectively reviewed. RESULTS: Influenza A was detected in 374 patients (83.7%), and influenza B in 72 (16.6%). The incidence of influenza A was highest in February (n=186), while that of influenza B was highest in March (n=36). The most common symptoms were fever (n=434, 97.1%) and cough (n=362, 81.0%). No significant differences were observed between influenza A and B in symptoms and laboratory data. Patients who had used oseltamivir within 2 days showed statistically lower admission rate, shorter admission duration, and lower incidence of pneumonia. CONCLUSION: This study found no statistical difference between influenza A and B, in symptoms, progression, and laboratory test, but those who were treated with oseltamivir given within 2 days of the onset of fever experienced more positive outcomes.

Comparisons of Clinical Features among Influenza A (H1N1) and Seasonal Influenza A and B during 2009 to 2010 at a Single Institution / 소아알레르기및호흡기학회지

PURPOSE: This study was performed to compare the clinical features of pediatric patients who were diagnosed with influenza A (H1N1) or seasonal influenza A and B during 2009 and 2010 at a single institution. METHODS: Among children who visited the Dong-A University Hospital with fever (>37.8degrees C) and acute respiratory symptoms from September 2009 to February 2010, 1,004 children who were diagnosed with influenza A (H1N1) or seasonal influenza A and B by reverse transcription-polymerase chain reaction (RT-PCR) were enrolled. Monthly incidence, fever duration before diagnosis, symptoms (fever, cough, rhinorrhea, sore throat, headache, vomiting, abdominal pain, diarrhea, seizure, and dyspnea) and signs (rales, wheezing) were reviewed retrospectively in each group based on medical records. RESULTS: Influenza A (H1N1) was detected in 944 patients (94.0%), followed by seasonal influenza A in 42 (4.2%) and seasonal influenza B in 8 (1.8%). The positive rate of influenza infection was highest in November 2009 (n=557, 55.5%). Mean duration of fever before RT-PCR was 1.6 days (range, 1.5 to 1.8 days). Except fever, cough was the most common symptom (n=792, 78.9%), followed by rhinorrhea in 407 patients (40.5%). Rales and wheezing were detected in 16 patients (1.6%) and 19 (1.9%), respectively. Significant differences were observed for the number of patients who had cough, headache, vomiting, and wheezing among the three groups (P<0.05). CONCLUSION: Although the incidence of cough, headache, vomiting, and wheezing differed significantly among the three groups, the number of patients in each group was too different to compare the results.

Interpretation of Positive Result for Influenza A and Negative Result for Novel Influenza A/H1N1 in Reverse Transcriptase PCR for Novel Influenza A/H1N1 / 임상검사와정도관리

BACKGROUND: Real-time reverse transcriptase PCR (rRT-PCR) is widely used to detect novel influenza A/H1N1. We had observed several cases with positive result for influenza A and negative result for novel influenza A/H1N1 during a novel influenza A/H1N1 outbreak. The causes of those results were investigated in this study. METHODS: A total of 913 cases tested with rRT-PCR for novel influenza A/H1N1 (Real-time Ready Influenza A/H1N1 Detection Set, Roche Diagnostics, Germany) during 25 August 2009 to 8 September 2009 was enrolled in this study. Cases showing positive result for influenza A (M gene) and negative result for novel influenza A/H1N1 (H1 gene) were tested with multiplex RT-PCR for seasonal influenza and novel influenza A/H1N1 (Seeplex FluA ACE Subtyping kit, Seegene, Korea), and the amplicons were directly sequenced. RESULTS: One hundred and eleven cases (12.2%) were positive for novel influenza A/H1N1. Twenty-seven cases (3.0%) were positive for influenza A, but negative for novel influenza A/H1N1. Subtypes of influenza A were determined in 25 cases by multiplex RT-PCR and nucleotides sequencing. One novel influenza A/H1N1, six seasonal influenza A/H1N1, three seasonal influenza A/H3N2, and 15 influenza A/H9N2 were detected. CONCLUSIONS: Subtypes of influenza A were determined in most cases with positive result for influenza A and negative result for novel influenza A/H1N1. Several cases with seasonal influenza A were detected. Even if a nonepidemic period of seasonal influenza, tests for seasonal influenza A can help in the differential diagnosis of influenza.