• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.218-224
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• 2000

Purpose : In Korea, vivax malaria has been reemerged since 1993 after being abscent for more than 10 years. There are several possibilities of casuality of recent epidemic, although it is still unclear. The epidemiologic studies including case analysis and entomological reseach have been undertaken for a successful control measure. But, unfortunately those studies have been rarely dealt with cases of children. Therefore, this study was designed to figure out the characteristics of epidemiolgic and clinical features in children with indigenous vivax malaria. Methods : The study 21 cases below 15 years of age, who were diagnosed as vivax malaria and resided in kyounggi-do province area during 1998. 9~1999. 8. We retrospectively analyzed epidemiologic data concernig with occurrence of vivax, and clinical manifestations, abnormal laboratory findings and outcomes including therapeutic responses. Results : All cases were inhabitants of the endemic areas for vivax malaria in northwestern part of Kyonggi-do or western Kangwon-do, and Paju-gun was the most prevalent. Indigenous malaria cases of this study were more prevalent in children above 10 years old age, and in male. Seasonally, vivax malaria in children occurred throughout the year except January, March and November, and the incidence was the highest in July. Clinical manifestations revealed that 48 hour cyclic fever pattern was the major fever pattern, and other symptoms such as headache, vomiting, poor appetites, chilling, abdominal pain and diarrhea were concomitantly developed. And splenomegaly revealed the main abnormal findings on physical examination, and anemia was the most frequent abnormal finding in laboratory examinations. Young trophozoite was frequently observed on peripheral blood smears. The therapeutic responses of chlorquine were very good in all cases, and no recurrence developed in follow up cases. Conclusion : Geographical and seasonal occurrence distributions of indigenous vivax malaria cases in children were very similar to those of adults as followings; Inhabitants of the endemic region, more prevalent in male, and more common during the summer season. Clinically, 48 hour cyclic fever pattern, splenomegaly and anemia were most frequent and important manifestations in children cases, and clinical courses were not serious. On blood smears, young trophozoite was most dominantly examined in children. Generally, the therapeutic outcomes were excellent, and recurrences were not observed.

• Pediatric Infection and Vaccine
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• v.5 no.1
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• pp.88-95
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• 1998

Purpose : Varicella is a common contagious illness and vaccine against it has been used in healthy Korean children. We studied clinical and epidemiologic features of varicella and the effect of vaccination. Methods : We analyzed clinical and epidemiologic features of varicella and vaccination effect against it in children treated in Hangang Sacred Heart Hospital from March 1994 to December 1996. Results : 1) Total 73 cases of varicella, 46 male and 27 female patients were included. Annual incidence was 31, 20 and 22 cases from '94 to '96 respectively, with an increase during the period June to July and December to January. 2) Mean age was $46{\pm}37.2$ months and 84.9% of the patients were younger than 7 years old including 16.4% of infants. 3) Varicella occurred after a contact with varicella patients in 40(54.8%) patients. 4) Fever developed in 44(60%) patients with mean $38.4{\pm}0.8^{\circ}C$ and persisted for mean $3{\pm}2.4$ days. Nine(12.3%) patients had complications and eighteen(25%) patients were admitted for mean $4{\pm}2.1$ days but all recovered. 5) Twenty(27.8%) patients were affected despite preceding vaccination against varicella but the number of vesicles decreased significantly in vaccinees(P<0.01). 6) The rate of secondary cases in healthy siblings was 27 out of 35(77.1%) and was not affected by preceding vaccination. Conclusion : Varicella occurred mainly in children younger than 7 years old and showed seasonality. Because 27.8% of cases developed despite preceding vaccination and the rate of secondary cases was not affected by vaccination, further study for vaccine efficacy is necessary.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.52-60
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• 2005

Purpose : The aim of this study is to know seasonal distribution of group A streptococci obtained from one center using emm genotyping and T serotyping in Masan from 2003 through 2004. Methods : Among children who visited the Changwon Fatima Hospital at Masan, Korea from June 2003 through February 2004, 100 patients who had clinical findings of acute pharyngitis, scarlet fever, and cellulitis were confirmed as GAS by culture, and were enrolled in our study. All obtained GAS were sent to the WHO Collaborative Center for Reference and Research on Streptococci, University of Minnesota, Minneapolis for T serotyping and emm genotyping. We classified these results again according to seasonal and disease's entities. Results : 19 different T serotypes was typed. T4(27.5%), T1(17.6%), T6(13.7%), and T12(13.7%) serotypes were relatively common in summer, while T4(28.3%), T12(15.2%), and T12/B3264(8.7%) were common in winter. T4 and T12 were persistent all year around. Distribution of T serotypes in 89 patients with pharyngotonsillitis were T4(26.7%), T12(14.0%), T1(12.8%), and T6(11.6%) in order of frequency. 15 different emm genotypes was typed. The number of emm 1, emm 6, emm 9, and emm 44 genotypes decreased or disappeared in winter, and the number of emm 3, emm 12, and emm 89 genotypes increased or reappeared in winter. Conclusion : Because T serotyping and emm genotyping are useful tools for evaluating epidemiology and pathogenesis of group A streptococci, we should monitor these strains every year, and should serotype and genotype GAS obtained from the invasive streptococcal infections.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.86-94
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• 2005

Purpose : Recently, it has been reported that the prevalence of mycoplasam pneumonia in infants is increasing. We studied the change of prevalence and clinical features in infants for recent three years. Methods : We evaluated the clinical records of 206 patients diagnosed as mycoplasma pneumonia during Mar. 2000~Feb. 2003. We retrospectively analyzed epidemiologic, clinical, serologic and radiologic difference between children younger than 24 months and others. Results : Among 206 patients, 111 were boys and 95 were girls. Mean age of onset was $5.12{\pm}2.91$ years and lowered annually(P>0.05). 28 patinets(13.6%) were younger than 24 months and annual prevalence in this group increased(P<0.05). Main clinical features included cough, fever, coarse breathing sound(=sputum), rhinorrhea and dyspnea. There was no clinical difference between children younger than 24 months and others, except for rhinorrhea and dyspnea which more developed frequently in children younger than 24 months (P<0.05). There was also no serologic and radiologic difference for these groups. Conclusion : Annual mean age of onset lowered and annual prevalence of younger than 24 months increased with mycoplasma pneumonia. Therefore, we need careful attention to differentiate Mycoplasma pneumoniae as causal organism of pneumonia in children younger than 24 months.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.61-66
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• 2005

Purpose : Since hepatitis A virus almost is transmitted by fecal-to-oral route, individual and public sanitation affects the prevalence and ages of hepatitis A infection. We researched the positivity rate of hepatitis A antibody at Pohang to make the basic data for subclinical infection and vaccination schedule. Methods : From January 2004 to February 2005, a total of 603 patients who were admitted at Hangdong University Sunlin Hospital, Dongguk University Hospital, and Christianity Hospital without any hepatic disease and vaccination of hepatitis A were enrolled. IgG antibody to hepatitis A virus were measured by electrochemiluminescence immunoassay(ECLIA). Results : Among 603 patients, 523 patients were less than 15 year of age and 80 patients were in above 15 years. The prevalence rate was 19.3%(101/523) in pediatric group and 70.0%(56/80) in above 15 years. In detail, the prevalence rate was 73.2%(52/71) in 0~5 months, 14.9%(11/74) in 6~11 month, 8.9%(7/79) in 12~17 month, 7.3%(6/82) in 18~23 month, 5.5%(4/72) in 2~3 years, 12.1%(9/74) in 4~8 years, 16.9%(12/71) in 9~14 years, 52.5%(19/40) in 15~29 years, and 92.5%(37/40) in group aged over 30 years. The prevalence rates in male and female showed no significant differences. Conclusion : The prevalence rate of hepatitis A in the group of 4~8 years and 9~14 years at Pohang was lower comparing with previous reports of other cities in Korea. We can postulate that the sanitation of children living at Pohang is at least not bad than other cities. And for the prevalence rate of hepatitis A is increased after 3 years, we should recommend that the vaccination of hepatitis A may be finished until 3 years.

• Pediatric Infection and Vaccine
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• v.9 no.2
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• pp.208-214
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• 2002

Purpose : The number of newborns vaccinated with BCG of Tokyo 172 strain, which has been claimed to cause lesser degree of local adverse events including scar, has recently been increasing. However, tuberculin response to this vaccine has inadequately been studied, especially with newborns cared at primary care clinics. We, therefore, performed a study in newborns vaccinated with BCG at private pediatric offices and evaluated the response to PPD 2TU or PPD 5TU following vaccination with percutaneous or intradermal BCG. Methods : Two hundred infants who had been cared at three private pediatric offices were retrospectively enrolled in the study. One hundred fifty one infants had received percutaneous BCG(Tokyo strain); 129 infants had had tuberuclin test with PPD 2TU and the rest of 22 infants with PPD 5TU. Forty nine infants had received intradermal BCG(28 infants Copenhagen strain, I infant French strain, 20 infants unknown); 35 infants had had tuberculin test with PPD 2TU, 14 infants(11%) with PPD 5TU. Results : In infants vaccinated with percutaneous BCG, the mean induration diameter in tuberculin test was significantly greater with PPD 5TU($12.4{\pm}3.5mm$) compared to PPD 2TU ($9.2{\pm}4.4mm$). In infants vaccinated with intradermal BCG, the mean induration diameters in tuberculin test were $5.7{\pm}5.1mm$ to PPD 2TU and $6.6{\pm}4.8mm$ to PPD 5TU, which were not significantly different. The tuberculin response to PPD 2TU was significantly greater in infants vaccinated with percutaneous BCG compared to those with intradermal BCG. The tuberculin response to PPD 5TU was also significantly greater in infants vaccinated with percutaneous BCG compared to those with intradermal BCG. Conclusion : Percutaneous BCG(Tokyo strain) seems to cause greater response to tuberculin compared to intradermal BCG and PPD 2TU induces weaker response compared to PPD 5TU. Acknowledging some discrepancies from the previously reported data, which might have been due to the different source of the study subjects, more studies are needed to establish the range of tuberculin response following BCG vaccination in order to differentiate from tuberculosis.

• Pediatric Infection and Vaccine
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• v.25 no.2
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• pp.72-81
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• 2018

Purpose: This prospective study aimed to investigate the therapeutic efficacy of lamivudine in children with chronic hepatitis B virus (HBV) infection. Methods: During July 2003 through October 2015, children with chronic hepatitis B who visited our institution were included in this study. Fifty-five patients, who received first-line treatment of lamivudine (3 mg/kg, 100 mg maximum) for over three months, were enrolled. After initiating lamivudine, alanine aminotransferase (ALT), HBV-DNA, and HBV markers were followed up at 1 month, 3 months, and every 3 months, thereafter. The treatment endpoint was determined as 1) normalization of ALT, 2) HBeAg seroconversion, and 3) anti-HBe positivity for twelve consecutive months. Results: Thirty-one male (56.4%) and 24 female (43.6%) patients were included. The mean age at treatment initiation was 8.1 years. The mean duration of treatment was 23.4 months. ALT normalization was found in 98.2% (54 of 55). Anti-HBe seroconversion was found in 70.6% (36/51). Loss of HBsAg was found in 10.9% (6/55). All biochemical responses occurred under age seven. The rate of virologic response (defined as HBV-DNA <2,000 IU/mL) at six months after treatment initiation was 78.7% (37/47). At twelve months after reaching treatment endpoint, 87.2% (34/39) maintained their virologic response. Resistance to lamivudine was found in 16.4% (9/55). Conclusions: Lamivudine treatment in Korean pediatric patients with chronic hepatitis B showed better outcomes compared with other studies that implemented similar protocols in foreign populations. Further studies are needed to investigate the efficacy of newly recommended antiviral drugs on the Korean pediatric population.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.85-94
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• 2002

Purpose: This study was performed for analysis of the results of polymerase chain reaction(PCR) and antibody test of Mycoplasma pneumoniae(M. pneumoniae) in children with symptoms of respiratory tract infection. In the cases of both positive antibody test and PCR for M. pneumoniae, the chest X-ray findings were assessed. Methods: The antibody test was done in 1,979 cases who have been admitted to Wonkwang university hospital department of pediatrics with symptoms of respiratory tract infection from January, 2000 to December, 2001. The positive antibody test was defined as titer of 1 : 80 and over 1 : 80. The PCR of M. pneumoniae were done in randomly selected 131 cases of respiratory tract infection. The chest X-ray findings were assessed in the cases of positive antibody test and PCR. Results: The numbers of cases of the positive antibody test for M. pneumoniae were 499 cases(25%). The PCR for M. pneumoniae were performed in 131 cases and the 45 cases(34%) were positive and 86 cases(66%) were negative. The 56 of 86 PCR negative cases were also negative antibody test, but 30 cases were positive antibody test. The 36 cases of 45 PCR positive cases were antibody positive, and 9 cases were antibody negative. The sputum Gram stain and culture for M. pneumoniae were negative in all the 499 cases of mycoplasma antibody positive respiratory infection. In these antibody positive 499 cases, the most common X-ray findings was interstitial pneumonic infiltration in 266 cases(53%), and pleural effusion were detected in 22 cases(4%), but nonspecific chest X-ray finding showed in 129 cases(26%). In PCR positive 45 cases, the most common chest X-ray finding was interstitial pneumonic infiltration in 32 cases(71%). Conclusion: The PCR for M. pneumoniae is more useful method for detection of mycoplasma infection in children with respiratory tract infection. The M. pneumoniae is a important etiologic agent for respiratory infection in children.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.225-231
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• 1997

Purpose: To evaluate the postnatal changes of serum levels of mumps- and rubella-specific IgG antibody in unvaccinated infants, this study was performed using enzyme linked immunosorbent assay(ELISA). The sera were collected from 103 unvaccinated infants under 15 months of age. The results obtained were as follows. 1) The seropositivities and the levels of mumps specific IgG decreased by ages, 70.6% in month, 50.0% in 2~3 months, 6.7% in 4~5 months and 0% after 6 months of age respectively. 2) The seropositivities of rubella-specific IgG were 58.8 % in 1 month, 70% in 2~3 months, 13.3% in 4~5 months, and 0% after 6 months of ages in unvaccinated infants respectively. 3) The seropositivities and antibody levels of mumps and rubella specific IgG had significantly decreased with age, and there was negative correlation between ages of infants and mumps or rubella-specific IgG levels(correlation coefficient r=-0.500, P < 0.001). Conclusions: The seropositivities of transplacental antibodies of mumps and rubella in unvaccinated infants were 0% after 6 months of age. These transplacental antibodies disappeared earlier age than we had thought.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.82-91
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• 2021

Background: The purpose of this study was to investigate the association between antibiotic use and the antimicrobial resistance of gram-negative bacteria isolated from blood cultures in a pediatric population. Methods: From January 2014 to June 2018, the antibiotic resistance pattern of Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa obtained from bacteremic patients aged ≤18 years hospitalized at Asan Medical Center Children's Hospital was analyzed and the parenteral antibiotic consumption data were retrieved. Results: During the study period, the blood culture was positive for K. pneumoniae (6.4%; 105/1,628), E. coli (5.6%; 91/1,628), P. aeruginosa (3.3%; 54/1,628), and A. baumannii (2.5%; 41/1,628), and the extended-spectrum antibiotic resistance rate of gram-negative bacteria was consistently high. The overall resistance rate of E. coli and K. pneumoniae to extendedspectrum cephalosporin was 49.3% and 54.4%, respectively. Carbapenem-resistant E. coli was first detected in 2014; its overall resistance rate to carbapenem was 5.3%. There was a linear correlation between the usage of 3rd generation cephalosporin and the resistance of A. baumannii (r²=0.96, P=0.004) and carbapenem usage and the resistance of K. pneumoniae (r²=0.79, P=0.045). Conclusions: A positive linear correlation was observed between antibiotic resistance and the corresponding antibiotic usage in 3rd generation cephalosporin resistant A. baumannii and carbapenem resistant K. pneumoniae. The judicious use of antibiotics in healthcare settings is important to minimize selection for extended-spectrum β-lactamase (ESBL) and carbapenem resistance in gram-negative bacteria.