• Pediatric Infection and Vaccine
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• v.20 no.2
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• pp.89-97
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• 2013

Purpose: This retrospective study was performed to identify the clinical characteristics of influenza B infection and compare to influenza A infection. Methods: Medical records of patients diagnosed with influenza using a multiplex PCR test, admitted to Seoul St. Mary's Hospital, during the 2011-2012 influenza season were analyzed. Clinical and laboratory characteristics of influenza B patients were investigated and compared with those of influenza A patients. Results: A total of 145 influenza patients were enrolled during this study period. Among these, 66 and 78 patients were diagnosed with influenza A and B, respectively, and 1 patient was diagnosed with co-existing influenza A and B. Cough (88.2%), rhinorrhea (77.1%) and sputum (60.4%) were the most common symptoms among these influenza patients, and most were diagnosed with upper respiratory infection (31.9%) or lower respiratory infection (49.3%). In comparison to influenza A patients, influenza B patients were older ($4.7{\pm}4.1$ years vs. $3.3{\pm}2.5$ years, P=0.016), and the number of fever days before hospitalization were longer (3.0 days vs. 2.5 days, P=0.043). While sore throat (10.3% vs. 1.5%, P=0.039) and vomiting (20.5% vs. 6.1%, P=0.012) were more common in influenza B patients than in influenza A patients, other clinical and laboratory characteristics were not significantly different between the two groups. Conclusions: No significant differences in clinical and laboratory perspectives were manifested in influenza A and B infections. Preventive measures should be emphasized over treatment in influenza B due to prolonged fever duration before admission.

• Tuberculosis and Respiratory Diseases
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• v.80 no.4
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• pp.392-400
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• 2017

Background: Most patients with influenza recover spontaneously or following treatment with an anti-viral agent, but some patients experience pneumonia requiring hospitalization. We conducted a retrospective review to determine the incidence and risk factors of pneumonia in hospitalized patients with influenza A or B. Methods: A total of 213 patients aged 18 years or older and hospitalized with influenza between January 2012 and January 2015 were included in this study. A reverse-transcriptase polymerase chain reaction assay was used to detect the influenza A or B virus in the patients' sputum samples. We collected demographic and laboratory data, combined coexisting diseases, and radiologic findings. Results: The incidence of pneumonia was higher in patients in the influenza A group compared to those in the influenza B group (68.6% vs. 56.9%), but this difference was not statistically significant. The presence of underlying respiratory disease was significantly associated with pneumonia in the influenza A group (adjusted odds ratio [OR], 3.975; 95% confidence interval [CI], 1.312-12.043; p=0.015). In the influenza B group, the white blood cell count (adjusted OR, 1.413; 95% CI, 1.053-1.896; p=0.021), platelet count (adjusted OR, 0.988; 95% CI, 0.978-0.999; p=0.027), and existence of an underlying medical disease (adjusted OR, 15.858; 95% CI, 1.757-143.088; p=0.014) were all significantly associated with pneumonia in multivariate analyses. Conclusion: The incidence of pneumonia was 65.7% in hospitalized patients with influenza A or B. The risk factors of pneumonia differed in hospitalized patients with influenza A or B.

• The Journal of the Korean Society for Microbiology
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• v.22 no.1
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• pp.9-13
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• 1987

During 31 days (5 week) from December 9th 1985 to January 8th 1986, Influenza B epidemic were observed in Seoul city. Epidemic peak was shown at 52nd week in 1985. The Epidemic associated viruses were determined as B/yamanish/510/84 and B/Ann Arbor/1/86-like strain. From total of 124 specimens of influenza-like illness children virus isolation rate were average 4.0%, much lower than that of influenza A virus isolation experience. In the epidemic influenza B infection were predominantly involved in school age children.

• Tuberculosis and Respiratory Diseases
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• v.84 no.3
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• pp.226-236
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• 2021

Background: Although the Quidel Sofia rapid influenza fluorescent immunoassay (FIA) is widely used to identify influenza A and B, the diagnostic accuracy of this test remains unclear. Thus, the objective of this study was to determine the diagnostic performance of this test compared to reverse transcriptase-polymerase chain reaction. Methods: A systematic literature search was performed using MEDLINE, EMBASE, and the Cochrane Central Register. Pooled sensitivity, specificity, diagnostic odds ratio (DOR), and a hierarchical summary receiver-operating characteristic curve (HSROC) of this test for identifying influenza A and B were determined using meta-analysis. A sensitivity subgroup analysis was performed to identify potential sources of heterogeneity within selected studies. Results: We identified 17 studies involving 8,334 patients. Pooled sensitivity, specificity, and DOR of the Quidel Sofia rapid influenza FIA for identifying influenza A were 0.78 (95% confidence interval [CI], 0.71-0.83), 0.99 (95% CI, 0.98-0.99), and 251.26 (95% CI, 139.39-452.89), respectively. Pooled sensitivity, specificity, and DOR of this test for identifying influenza B were 0.72 (95% CI, 0.60-0.82), 0.98 (95% CI, 0.96-0.99), and 140.20 (95% CI, 55.92-351.54), respectively. The area under the HSROC for this test for identifying influenza A was similar to that for identifying influenza B. Age was considered a probable source of heterogeneity. Conclusion: Pooled sensitivities of the Quidel Sofia rapid influenza FIA for identifying influenza A and B did not quite meet the target level (≥80%). Thus, caution is needed when interpreting data of this study due to substantial betweenstudy heterogeneity.

• Journal of Life Science
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• v.8 no.6
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• pp.667-672
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• 1998

This study was done to detect the causative agent of patient with respiratory disease in Pusan, 1997. Male and female patients with respiratory disease in Pusan, 1997, were 31.9% and 68.1 ％, respectively. In the aspect of out-break by month, patients with respiratory disease were mostly concentrated at February, March, April, October, November and December. Fifteen strains of influenza virus were isolated from 1,268 swabbed samples of throat, and thirteen strains and 2 strains among 15 isolates were classified with influenza A and B virus, respectively. One of 13 influenza A virus was confirmed as A/Johannesburg/33/94- like strain, and the other isolates of influenza A virus were confirmed as A/sydney/05/97-like strains. Two isolates of influenza B virus were confirmed as B/Bei-jing/08/93-like strains.

• Pediatric Infection and Vaccine
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• v.21 no.1
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• pp.1-8
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• 2014

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.

• Pediatric Infection and Vaccine
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• v.24 no.1
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• pp.23-30
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• 2017

Purpose: The objective of this study was to compare the clinical characteristics of influenza A and B infections and analyze the effect of oseltamivir in hospitalized children. Methods: We investigated children under the age of 15, who were diagnosed with influenza A/H1N1, A/H3N2, or B from January to April 2014. The subjects were admitted to the Changwon Fatima Hospital and diagnosed using a rapid antigen test from nasopharyngeal swabs. The medical records of the patients were retrospectively reviewed. Results: A total of 302 pediatric patients with influenza were enrolled. Influenza B infection was the most common type (n=187, 61.9%), followed by A/H3N2 (n=100, 33.1%) and A/H1N1 (n=15, 5.0%). Compared to patients diagnosed with influenza A, patients diagnosed with influenza B were older (P=0.005), and the duration of fever was significantly longer (P=0.001). A total of 161 patients (53.3%) had been vaccinated against influenza during the season, before admission. Among the patients infected with A/H3N2 and B, the duration of fever was shorter in oseltamivir recipients compared to oseltamivir non-recipients (P=0.026 and P=0.004, respectively). Conclusions: There were significant differences between influenza A and B groups in terms of age, demographics, and clinical course. Although the effectiveness of oseltamivir on influenza differs according to the type of influenza, our data provides evidence that oseltamivir is beneficial for both A and B infections.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1683-1690
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• 2018

Accurate and rapid diagnosis of influenza infection is essential to enable early antiviral treatment and reduce the mortality associated with seasonal and epidemic infections. Immunochromatography is one of the most common methods used for the diagnosis of seasonal human influenza; however, it is less effective in diagnosing pandemic influenza virus. Currently, rapid diagnostic kits for pandemic influenza virus rely on the detection of nucleoprotein (NP) or hemagglutinin (HA). NP detection shows higher specificity and is more sensitive than HA detection. In this study, we time-dependently screened expression conditions, and herein report optimal conditions for the expression of recombinant nucleoprotein (rNP), which was 48 h after infection. In addition, we report the use of the expressed rNP in a rapid influenza diagnostic test (SGT i-flex Influenza A&B Test). We constructed expression vectors that synthesized rNP (antigen) of influenza A and B in insect cells (Sf9 cells), employed the purified rNP to the immunoassay test kit, and clearly distinguished NPs of influenza A and influenza B using this rapid influenza diagnostic kit. This approach may improve the development of rapid test kits for influenza using NP.

• Clinical and Experimental Pediatrics
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• v.56 no.4
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• pp.165-175
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• 2013

Purpose: There was a global increase in the prevalence of oseltamivir-resistant influenza viruses during the 2007-2008 influenza season. This study was conducted to investigate the occurrence and characteristics of oseltamivir-resistant influenza viruses during the 2007-2008 and 2008-2009 influenza seasons among patients who were treated with oseltamivir (group A) and those that did not receive oseltamivir (group B). Methods: A prospective study was conducted on 321 pediatric patients who were hospitalized because of influenza during the 2007-2008 and 2008-2009 influenza seasons. Drug resistance tests were conducted on influenza viruses isolated from 91 patients. Results: There was no significant difference between the clinical characteristics of groups A and B during both seasons. Influenza A/H1N1, isolated from both groups A and B during the 2007-2008 and 2008-2009 periods, was not resistant to zanamivir. However, phenotypic analysis of the virus revealed a high oseltamivir $IC_{50}$ range and that H275Y substitution of the neuraminidase (NA) gene and partial variation of the hemagglutinin (HA) gene did not affect its antigenicity to the HA vaccine even though group A had a shorter hospitalization duration and fewer lower respiratory tract complications than group B. In addition, there was no significant difference in the clinical manifestations between oseltamivir-susceptible and oseltamivir-resistant strains of influenza A/H1N1. Conclusion: Establishment of guidelines to efficiently treat influenza with oseltamivir, a commonly used drug for treating influenza in Korean pediatric patients, and a treatment strategy with a new therapeutic agent is required.

• Pediatric Infection and Vaccine
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• v.19 no.1
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• pp.1-11
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• 2012

Purpose : Although influenza is regarded as one of the major causes of morbidity and mortality in children with cancer, the actual vaccine coverage remains poor. We conducted evaluation of immunogenicity and safety of influenza vaccine in children with cancer. Methods : In this study, 25 children with cancer who received influenza vaccine (SK influenza IX vaccine$^{(R)}$) at the Korea Cancer Center Hospital between October and December 2009 were analyzed. Blood samples of patients were collected twice (at the beginning of this study and at 30th day after vaccination) and their antibody titers were measured using the hemagglutination-inhibition (HI) assay. Immunogenicity of the influenza vaccine was assessed by seroprotection rate on days 0 and 30, seroconversion rate on day 30, and mean fold increase (MFI) of geometric mean titer (GMT) of HI between days 0 and 30. Results : Any of the subjects in our study did not experienced serious adverse events after influenza vaccination. Seroprotection rates were 68% for H1N1, 40% for H3N2, and 36% for B. Seroconversion rates were 12% for H1N1, 16% for H3N2, and 20% for B. MFIs were 0.9 for H1N1, 1.2 for H3N2, and 1.8 for B. Conclusion : In the study, we found a limited protective immune response to influenza vaccine, among subjects with cancer. However, some subjects showed seroconversion, and there were no severe adverse events among all subjects, supporting the recommendation of annual influenza vaccination in children with cancer.