• Pediatric Infection and Vaccine
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• v.25 no.1
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• pp.35-44
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• 2018

Purpose: This study aimed to evaluate the immunogenicity and safety of a trivalent inactivated influenza vaccine (TIV) among healthy Korean children and adolescents. Methods: From October to December 2008, 65 healthy patients aged 6 months to 18 years who visited Korea University Ansan Hospital for influenza vaccination were enrolled in this study. We measured the hemagglutinin inhibition antibody titers at baseline and 30 days after vaccinating enrollees with split influenza vaccine and calculated the seroprotection rates, geometric mean titers, and seroconversion rates. Local and systemic adverse events were assessed after vaccination. Results: The seroprotection rates against all three viral strains (A/H1N1, A/H3N2, B) were 87.7%, 89.2%, and 89.2% (${\geq}70%$), respectively; seroconversion rates were 44.6%, 73.8%, and 63.1% (${\geq}40%$), respectively; and seroconversion factors were 4.5, 8.4, and 10.5 (>2.5), respectively. The TIV immunogenicity was acceptable according to the CPMP (Committee for Proprietary Medicinal Products) criteria. Although 48 patients (73.8%) reported one or more adverse events, no severe adverse events such as anaphylaxis and convulsion were observed. Forty-two patients (64.6%) reported a local skin reaction, including redness (29.2%), pain (43.1%), or swelling (41.5%) of the injected site, and 26 (40.0%) reported a systemic reaction: fatigue (23.1%), myalgia (20.0%), headache (10.8%), arthralgia (10.8%), chills (9.2%), or fever (7.7%). Conclusions: This study shows that the immunogenicity of the TIV vaccine is acceptable. As there were no serious adverse events aside from local reactions and mild systemic reactions, this vaccine can be safely used among healthy Korean children and adolescents.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.40-46
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• 2009

Purpose : The purpose of this study was to identify useful predictors for diagnosing bacterial meningitis and performing CSF studies in febrile infants three months or younger. Methods : Six hundred and fifty two febrile infants with a rectal temperature ${\geq}38.0^{\circ}C$ presented from January 2003 to April 2008 and were retrospectively studied. The total white blood cell count (WBC), band count, absolute neutrophil count (ANC), quantitative C-reactive protein (CRP) and blood cultures were performed on admission. The clinical variables associated with bacterial meningitis were analyzed. Results : In patients with bacterial meningitis, the clinical variables including CRP (P=0.036), band count (P=0.037), ANC (P=0.036) and age (P=0.001) were significantly different. The area under the receiver-operating characteristic curve was 0.969 for CRP, 0.946 for the band count, 0.765 for the ANC and 0.235 for age. A CRP cutoff point of 8 mg/dL was determined to maximize both the sensitivity and specificity (sensitivity 83%, specificity 95%, likelihood ratio 16.6). A CRP concentration of <7 mg/dL "ruled-out" bacterial meningitis, with a likelihood ratio of 0.17, a posttest probability of <0.1% and negative predictive value 91%. A CRP concentration greater than 9 mg/dL had a much higher likelihood ratio (20.1) than the band count (16.6) and ANC (2.2). Conclusion : The CRP concentration was a useful laboratory test for the differential diagnosis of bacterial meningitis among febrile infants three months of age or younger. A CRP concentration of <7 mg/dL effectively ruled out bacterial meningitis; a value ${\geq}9mg/dL$ increased the clinical suspicion of bacterial meningitis and the need for CSF evaluation.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.80-86
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• 2009

Purpose : This study was performed to determine the clinical course of BCG lymphadenitis. Methods : Between May 2005 and April 2009, the medical records of 33 patients with BCG lymphadenitis were retrospectively reviewed. If needed, needle aspiration was recommended without surgical resection or antituberculous medication. Results : Of the 33 patients who were identified, 21 were males and 12 were females. Among the 33 patients, 32 were full-term babies. The mean age was 6 months (range, 2-35 months) and the most prevalent site of the lesion was the left axilla. BCG lymphadenitis was observed 1-34 months after BCG vaccination, mostly 1-6 months after vaccination. The size of the enlargement was generally 1-3 cm. The strains were identified as French (n=14), Danish (n=7), and Tokyo (n=12). BCG lymphadenitis regressed spontaneously in 19 patients. After 1-5 needle aspirations, 14 patients recovered completely. Complete regression of lymphadenitis was recorded over an average period of 4 months. Conclusion : Clinicians need to be aware of the clinical features of BCG lymphadenitis. For management of BCG lymphadenitis, regular follow-up with observation should be the mainstay. Needle aspiration is a safe and easy treatment for suppurative BCG lymphadenitis.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.73-79
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• 2009

Purpose : We undertook this study to improve our understanding of the epidemiologic and clinical features of nonpolioenterovirus (NPEV) infections, especially enterovirus 71 (EV71) infections, in Korean children. Methods : Between April and June 2000, NPEVs were detected by RT-PCR and cultures of specimens obtained from patients with aseptic meningitis, acute respiratory disease, and acute gastroenteritis which were associated with enteroviral exanthem and vesicular pharyngeal enanthem, such as herpangina, and hand, foot, and mouth disease (HFMD). EV71 was identified by sequencing the VP1 gene. The clinical and epidemiologic data were analyzed retrospectively after all 87 NPEV-positive patients were divided into 4 groups, according to the clinical manifestations. Sixteen patients who mainly had symptoms of acute gastroenteritis were in group A, 21 patients with symptoms and signs of lower respiratory tract infections were in group B, 42 patients with a HFMD rash only were in group C with or without fever, and 8 patients with aseptic meningitis or paralysis were in group D. For the 11 EV71-positive patients, 1 was in group A, 2 were group B, 7 were in group C, and 1 was in group D. Results : There were 87 NPEV infections, including 11 EV71 infections. The mean age of the patients was 2 years and 11 months, ranging from 1 day to 15 years. There were no fatal cases among a total of 87 NPEV infections and no significant differences in clinical severity between the EV71 and other NPEV infections. Conclusion : NPEV infections in children were common during the 3 months in the spring of 2000. Unlike in southeast Asia, where fatal EV71 infection outbreaks have occurred since 1997, the clinical features of EV71 infection in Korean children are mild.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.31-39
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• 2009

Purpose : Neisseria meningitides is one of the most common causative pathogens of bacteremia and meningitis. Recently protein-conjugated vaccines have been developed and included in the routine vaccination schedule in a few countries. In Korea, carriage rates of N. meningitides among healthy adults have been reported. However, systematic data for childhood carriage rates are not available. This study was performed to evaluate the carriage rates of N. meningitides and the serotype distribution among healthy children attending day care centers. Methods : During the period of January through May 2005, nasopharyngeal swabs and culture were obtained from 904 children attending 13 different day care centers located in Seoul and Gyeonggi Province. The Vitek NHI card was used to identify N. meningitides and the crgA gene was detected via polymerase chain reaction (PCR). Serotype determination was performed by agglutination test using N. meningitides antisera to serotypes A, B, C, D, 29E, W135, X, Y, and Z. PCR for detection of the org2 and saiD gene confirmed serotypes A, B, C, W135, and Y. Results : The mean age among 904 children was 4.5 years; 6.5% (59/904) were children <2 years old, 53.8% (486/904) were 2-5 years old, and 39.7% (359/904) were >5 years old; 52.0% (468/904) were male. N. meningitides was isolated from only 7 children attending 5 different day care centers and the overall carriage rate of N. meningitides was 0.8%. The detected serotypes of N. meningitides were serotype A (n=2), C (n=2), and Y (n=3). Conclusion : The carriage rate of N. meningitides among healthy children attending day care centers was very low in Korea and the detected serotypes were A, C, and Y.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.61-72
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• 2009

Purpose : We evaluated the clinical features of Norovirus gastroenteritis compared with Rotavirus gastroenteritis in hospitalized children. Methods : We detected causative agents in 3,261 samples of children hospitalized with gastroenteritis symptoms at a single center of pediatrics between 2005 and 2006. Among 266 and 303 samples which tested positive for Norovirus and Rotavirus, we selected 73 and 182 samples of children with relatively pure gastroenteritis symptoms and retrospectively analyzed the corresponding medical records. Results : The male-to-female ratio of the Norovirus (+) and Rotavirus (+) groupswas 1.43:1 and 1.56:1 both groups were predominantly in males. The mean age of the Norovirus (+) and Rotavirus (+) groups was 36.7 and 24.4 months, respectively the children in the former group were older than the children in the latter group. The incidence in the Norovirus (+) group was more concentrated in the winter. The symptoms in the Norovirus (+), in decreasing order, included vomiting, diarrhea, and fever. The duration of vomiting, diarrhea, and fever was 2.1, 1.2, and 1.2 days. The maximum number of episodes of vomiting and diarrhea per day was 3.5 and 4.5, respectively. The severity score was 10.16. The symptoms inthe Rotavirus (+) group, in decreasing order, included diarrhea, vomiting, and fever. The duration of diarrhea, vomiting, and fever was 2.2, 4.3, and 2.2 days, respectively. The maximum number of episodes of vomiting and diarrhea per day was 3.3 and 6.5, respectively. The severity score was 11.9. The severity in the Norovirus (+) group was somewhat lower than the Rotavirus (+) group. The younger the child, the more severe the symptoms in the Norovirus (+) group. There was no difference between mono-and co-infection in severity and between the two groups regarding the hematologic findings. Conclusion : Based on the findings reported herein, additional studies about prophylaxis, as well as the epidemiology and clinical features of pediatric Norovirus gastroenteritis, are required.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.172-177
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• 2015

Purpose: This study aimed to analyze the epidemic period of RSV infection and evaluate the appropriate time of palivizumab immunoprophylaxis. Methods: From January 1991 to July 2012, nasopharyngeal (NP) aspirates were obtained from patients who visited Seoul National University Children's Hospital for respiratory symptoms. NP samples were used to detect respiratory viruses. Among them, we analyzed the positive number and detection rate of RSV infection in two-week interval. The beginning of RSV season was defined when RSV positive number was more than 4 and RSV detection rate was over 10%. From January 2007 to March 2014, we analyzed the starting time of palivizumab immunoprophylaxis for the infants at high risk. Results: The RSV detection rate was 2,013/21,698 (9.69%) over 22 years. The median RSV season was from $2^{nd}-3^{rd}$ week of October to $1^{st}-2^{nd}$ week of February. The earliest starting week was the 3rd week of July in year 2001, and the latest end week was the 3rd week of May in year 1990. Palivizumab immunoprophylaxis was initiated most frequently at the 3rd week of October (18.7%). However, the percentage of starting palivizumab on the 1st week of September has increased from 3.8% in the year 2007 to 14.1% in 2013. Conclusions: The year to year variability of RSV season exists. The starting time of palivizumab immunoprophylaxis should be adjusted based on the season of RSV epidemic.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.154-163
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• 2015

Purpose: Osteoarticular infections in children and adolescents are important because it can cause functional compromise if appropriate treatment is delayed. Therefore, this study was designed to describe the clinical presentations and causative organisms of osteoarticular infections in children and adolescents in order to propose early diagnosis method and an appropriate empiric antimicrobial therapy. Methods: Forty-two medical records were reviewed retrospectively, which were confirmed as osteomyelitis (OM) or septic arthritis (SA) at Department of Pediatrics or Orthopedic Surgery in patients under 18 years old of Ewha Womans University Mokdong Hospital from March 2008 to March 2015. Results: We identified 21 cases of OM, 13 cases of SA and 8 cases of OM with SA. There were 31 males and 11 females and mean age was 7.1 years old. The most common symptoms were pain and tenderness of involved site. Major involved bones were femur (10 cases, 34.5%), tibia (7 cases, 24.1%) and major involved joints were hip (9 cases, 42.9%), and knee (5 cases, 23.8%). Increased serum C-reactive protein and erythrocyte sedimentation rate were observed in 37 cases (88.1%) respectively. Magnetic resonance imaging was performed in 40 cases among 42 cases and was used to demonstrate osteoarticular infections and other adjacent infections. Nine cases (23.7%) among 38 cases and 20 cases (50.0%) among 40 cases were positive in blood culture and infected site culture respectively. The most common causative organism was Staphylococcus aureus, which was represented in 22 cases (75.9%), of which nine cases (40.9%) were resistant to methicillin. Conclusions: S. aureus was the most common causative organism of osteoarticular infections in children and adolescents and the proportion of MRSA was high in this study. Therefore, we recommend vancomycin as the first empiric antimicrobial therapy and suggest that further study is necessary to elucidate an appropriate guideline for treatment which takes into account MRSA proportion.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.79-86
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• 2017

Purpose: This study was aimed at analyzing the serotypes of group B streptococcus (GBS) isolated from Korean infants with invasive disease and evaluating their association with disease manifestation. Methods: Data were retrospectively collected from invasive GBS infections at Gachon University Gil Medical Center from January 2006 to June 2012 and at Samsung Medical Center from April 2010 to November 2012. Serotypes were determined by slide agglutination test. Results: A total of 37 cases were identified, which included 22 full-term infants and 15 preterm infants. Fifteen cases (40.5%) were early-onset, 19 (51.4%) was late-onset, and three (8.1%) was very late-onset. Early-onset diseases among preterm infants were higher than those among full-term infants (60.0% [9/15] vs. 27.3% [6/22], P=0.17). The most common manifestation was bacteremia (70.3%), followed by meningitis and septic arthritis. Among 24 isolates retrievable for serotyping, serotype III (41.7%) was most common, followed by V (16.7%), Ia, Ib, and II (12.5%, respectively), and non-typeable (4.2%). Serotype III was more common in isolates from full-term infants (10/22) than from preterm infants (0/15), whereas serotype V was more common in isolates from preterm infants (4/15) than from full-term infants (0/22) (P=0.002). No penicillin-resistant strain was detected, and resistance to erythromycin and clindamycin were both 64.9%. Conclusions: GBS is an important pathogen in both preterm and full-term infants, and serotype distribution of GBS causing invasive diseases can differ between preterm and full-term infants. It is necessary to monitor the nationwide epidemiology of GBS diseases, including in preterm infants, in order to prepare preventive measures without underestimating early-onset diseases.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.71-78
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• 2017

Purpose: The aim of this study was to identify the pathogens of blood stream infection (BSI) in children with hemato-oncologic disorders, to analyze susceptibility patterns of microorganisms to guide empirical antimicrobial therapy, and to compare temporal trends of the pathogen and antimicrobial susceptibility with those of previous studies. Methods: We retrospectively analyzed the medical records of children with hemato-oncologic disorders whose blood culture grew pathogens at the Seoul National University Children's Hospital between 2011 and 2015. Results: A total of 167 patients developed 221 episodes of bacteremia. Among 229 pathogens, gram-negative bacteria (GNB) accounted for 69.0% (64.0% in 2002 to 2005, 63.4% in 2006 to 2010); gram-positive bacteria (GPB) accounted for 28.8% (31.3% in 2002 to 2005, 34.6% in 2006 to 2010); and fungus accounted for 2.2%. Among GNB, Klebsiella species (53.2%, 84/158) and Escherichia coli (19.6%, 31/158) were common. Staphylococcus aureus (48.5%, 32/66) and viridans streptococci (21.2%, 14/66) were frequently isolated among GPB. The susceptibilities of oxacillin and vancomycin in GPB were 54.8% and 96.9% (51.5% and 95.5% in 2002 to 2005; 34.1% and 90.5% in 2006 to 2010), respectively, whereas in GNB, the susceptibilities of cefotaxime, piperacillin/tazobactam, and imipenem were 73.2%, 77.2%, and 92.6% (75.9%, 82.8%, and 93.4% in 2002 to 2005; 62.8%, 82.9%, 93.8% and in 2006 to 2010), respectively. There were no significant differences in the proportion of etiologic agents or the antimicrobial susceptibilities between the current study and that of the previous two studies from 2002 to 2010. Overall fatality rate was 13.1%. Conclusions: GNB predominated in BSI among children with hemato-oncologic disorders. The etiology of bacteremia and antimicrobial susceptibility were comparable to those of the previous studies. Thus, piperacillin/tazobactam can be used as the initial empirical antimicrobial agent in febrile neutropenia.