• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.232-239
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• 1997

Purpose: The incidence of hepatitis A virus(HAV) infection has markedly decreased in the last 20 years due to industrialization and improvements in the standard of living and hygiene in Korea. The reduction in seroprevalence rates indicates infection potential for young adult population, and a need for vaccinations in high-risk adults and children groups has been suggested. In this study we evaluated the seroprevalence rates and natural infection rates of hepatitis A in children and adolescent to obtain the basic data for vaccination of hepatitis A. Methods: A total of 334 children and adolescent subjects below 20 years old in Kyonggi-do province were examined for HAV antibody and seroprevalence rates in each age group was investigated. In 584 elementary school students residing in Kyonggi-do province, serum samples collected in 1993 and 1996 from the same subjects for investigation of natural seroconversion rates. Method of testing antibody was enzyme immunoassay. Results: 1) The seropositive rate of HAV in 334 subjects aged below 20 years old was 5.4%. According to age, the seropositive rates were 27.3% in infant group, 0.0% in 1~4 year-old group, 0.0% in 5~9 year-old group, 2.9% in 10~14 year-old group and 15.0% in 15~19 year-old group. 2) In the study of 584 elementary school children, only one subject showed seropositive in 1993, and in 1996 three different subjects showed seropositive results(0.5%); the natural seroconversion rate during 3 years was 0.5%. 3) The seroprevalence rates of below 20 year-old subjects reported in previous studies were 63.8% in 1979 and 47.3% in 1989 while the present study showed the rate at 5.4%. Conclusion: Since natural antibody formation is rarely occurring, there is a high risk for apparent hepatitis A infection in adults. Therefore vaccination in high risk groups is essential at present, and in order to reduce the chance for hepatitis A infection in adults, vaccination in children may be needed.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.135-142
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• 2011

Purpose : Hospital associated infection (HAI) caused by multidrug-resistant (MDR) microorganisms has been recognized as an important issue in the world, especially in critically ill patients such as the patients admitted in the intensive care unit. There are fewer papers about MDR-HAI in pediatric patients compared to adult patients. In this study, we investigated the incidence and associated factors of MDR-HAI in children admitted to the intensive care unit (ICU) of a university hospital. Methods : We retrospectively evaluated 135 children who were admitted in ICU for at least 3 days between January 2009 and December 2010. HAI cases were divided into MDR-HAI group and non-MDR-HAI group. Clinical characteristics and various associated factors were compared between those groups. Results : In 39 patients, 45 cases of ICU-related HAI were developed. ICU-related HAI incidence was 47.7 per 1000 patientdays. Thirty-six cases (80.0%) were MDR-HAI. Acinetobacter baumannii was isolated more commonly in MDR-HAI group. And the followings were found more frequently in MDR-HAI group than non-MDR-HAI group: medical condition as an indication for ICU admission, mechanical ventilation, urinary catheterization and previous use of broad-spectrum antibiotics. Among the risk factors, previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. Conclusion : ICU-related HAI incidence was higher than previously reported. Previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. To investigate the characteristics of MDR-HAI in children admitted in ICU, further studies with a larger sample size over a longer period of time are warranted.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.109-116
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• 2011

Purpose : Pneumococcus is one of the most important causes of invasive infection through the childhood period. In January 2008, the Clinical and Laboratory Standards Institute (CLSI) published revised penicillin breakpoints for Streptococcus pneumoniae and penicillin susceptibility rates of S. pneumoniae increased in Korea. This study was performed to determine the probability of oral amoxicillin for the empirical treatment achieving bactericidal exposure against pneumococcus using pharmacodynamics model. Methods : Twenty-three isolates of pneumococci were subjected to determine minimum inhibitory concentration (MIC) for ${\beta}$-lactams and macrolide. For the ${\beta}$-lactams, exposure of fT >MIC (time that free drug concentrations remain above the MIC) for 50% of the administration interval have determined the probability of target attainment (PTA), and regimens that had a PTA >90% were considered optimal. An analysis was performed by applying MIC of 23 isolates to a 5000-patient Monte Carlo simulation model. Results : Among 23 isolates from healthy children, 7 (30.4%) isolates were MIC ${\leq}$1.0 ${\mu}g$/mL and 19 (82.6%) were MIC ${\leq}$2 ${\mu}g$/mL for amoxicillin. Amoxicillin 40 mg/kg/day achieved PTA >90% at MIC ${\leq}$1.0 ${\mu}g$/mL but PTA decreased to 52% at MIC 2 ${\mu}g$/mL, whereas amoxicillin 90 mg/kg/day can predict 97% of PTA at MIC 2 ${\mu}g$/mL. Overall, oral amoxicillin 90 mg/ kg/day for the empirical treatment against pneumococcus can expect more successful response in Korean children. Conclusion : Considering the resistantce pattern of pneumococci in Korean children, we estimate that oral amoxicillin 90 mg/kg/day will provide a pharmacodynamic advantage for the empirical treatment against pneumococcus. And low dose amoxicillin or macrolide are expected to have higher chance of treatment failure than high dose oral amoxicillin.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.182-192
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• 2011

Purpose : Atopic findings may be associated with severity of pneumonia in 2009 pandemic influenza A (H1N1) infection, which could suggest a possible association between atopic findings and the severity of viral infections. Thus, we studied association between atopic findings and severity of disease in children with H1N1 influenza infection. Methods : A retrospective study was performed in 74 children admitted in a single tertiary institute and confirmed as H1N1 patients by reverse transcriptase (RT) - polymerase chain reaction (PCR). They were divided into 2 groups according to the severity of pneumonia. We evaluated whether the atopic finding is risk factor between the two groups. Results : Children with severe pneumonia had higher percentages of serum eosinophilia (88% vs 40%, P <0.001), asthma (65% vs 35%, P =0.011), allergic rhinitis (71% vs 40%, P =0.009), and IgE level (P =0.007). We found positive correlations between aeroallergen sensitizations and severity of pneumonia (82% vs 53%, P =0.007). Conclusion : Among patients with H1N1 pneumonia, asthma and atopic findings are risk factors for severity of pneumonia.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.193-200
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• 2011

Purpose : The effect of corticosteroid on severe pneumonia caused by 2009 pandemic influenza (H1N1) A virus is controversial. This study was aimed to present the effects of early, short-term corticosteroid treatment for severe pneumonia with this virus infection. Methods : A retrospective analysis was performed on severe pneumonia patients (37 patients) who had severe respiratory distress at presentation requiring oxygen therapy and received intravenous methylprednisolone (MP, 8-10 mg/kg, divided in 4 doses/day for 2-3 days) with oseltamivir. The clinical and laboratory characteristics of the patients were evaluated through the medical records and chest radiographic findings. Results : The mean age and male-to-female ratio of the patients were 6.5${\pm}$2.9 years of age, and 3.4:1 (male 29 patients), respectively. The 5-9 aged group was predominant among the age groups (25 patients, 67.6%). Duration of fever prior to admission was 1.4${\pm}$0.6 days and dyspnea developed within 24 h after beginning of respiratory symptoms in all patients. All patients were previously healthy and received oseltamivir within 48 h. Thirteen patients (35.1%) developed dyspnea during oseltamivir treatment. Following MP infusion, all 37 patients including 13 progressive pneumonia patients during oseltamivir treatment showed an immediate halt in the progression of pneumonic infiltration with rapid clinical improvement. There were no side-effects following steroid use. Conclusion : For severe pneumonia patients, early corticosteroid treatment halted clinical exacerbation, and possibly prevented progression to acute respiratory distress syndrome. Further controlled clinical studies are needed for the role of corticosteroids and antivirals on severely affected patients with influenza virus infections.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.163-172
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• 2011

Purpose : The purpose of this study was to review our recent experiences with deep neck abscesses in children and adolescents and to provide helpful information in treatment and diagnosis by comparing them with those in other available literatures. Methods : Medical records of 36 children and adolescents admitted for deep neck abscess at two hospitals from January 2000 to October 2010 were reviewed retrospectively. Results : Male to female ratio was 1.4 : 1 and the mean age was 6.5 years. Painful neck swelling and fever were the most frequent symptoms in patients under thirteen years of age whereas trismus and headache were frequent symptoms in patients over fourteen years of age. Submandibular space was the most common site of deep neck abscess in patients under thirteen years of age, whereas peritonsillar space was the most common site in patients over fourteen years of age. The results of bacterial cultures were positive in 61.5% of drained cases. Staphylococcus aureus was the most commonly identified bacteria in 6 patients (37.5%) and 5 of them were under 2 years of age. Twenty six patients received surgical drainage while the others were treated with antibiotics only. There were no statistically significant differences in the durations of admission, fever after admission, and antibiotic treatment between surgical and medical treatment groups. Conclusion : The common sites of deep neck abscess, associated symptoms, and causative organisms were different between children and adolescents. As there were no differences in durations of admission, fever, or antibiotics treatments between surgical and medical treatment groups, surgical drainage may be avoided by early recognition and suspicion. However, if there is no improvement of symptoms or size of abscesses within 48-72 hours of antibiotic treatment, surgical drainage should be considered.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.154-162
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• 2011

Purpose : The aim of this study was to identify the clinical characteristics of lower respiratory tract infection due to respiratory syncytial virus (RSV) in young children and to provide information for an effective guideline for palivizumab administration in Korea. Methods : We reviewed medical charts of 167 patients under 3 years of age who were hospitalized in Dongguk University Ilsan Hospital for lower respiratory tract infection between January 2007 and February 2011. Diagnosis of the virus was made based on the multiplex real time polymerase chain reaction. Results : There were 113 patients who were infected by respiratory syncytial virus. 90 patients were term infants and 23 patients were preterm infants. No difference was shown between term and preterm infants except the days of admission which was 9.0${\pm}$6.0 days and 12.6${\pm}$21.0 days respectively. In the preterm group their mean age at the time of admission was 5.21${\pm}$4.9 months and the mean gestational age was 33.1${\pm}$4.3 weeks, and the mean birth weight was 2,152${\pm}$950 g. Only 4 patients were born under 28 weeks gestational age and were candidates for palivizumab administration. Conclusion : Most of the patients with severe RSV lower respiratory tract infection were term or near term infants who were not candidates for palivizumab prophylaxis. A nationwide study is needed to make a new risk stratified guideline for RSV prophylaxis for our country.

• 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.