Twenty-Five Year Trend Change in the Etiology of Pediatric Invasive Bacterial Infections in Korea, 1996–2020

Background@#The coronavirus disease-2019 (COVID-19) pandemic has contributed to the change in the epidemiology of many infectious diseases. This study aimed to establish the pre-pandemic epidemiology of pediatric invasive bacterial infection (IBI). @*Methods@#A retrospective multicenter-based surveillance for pediatric IBIs has been maintained from 1996 to 2020 in Korea. IBIs caused by eight bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyogenes, Listeria monocytogenes, and Salmonella species) in immunocompetent children > 3 months of age were collected at 29 centers. The annual trend in the proportion of IBIs by each pathogen was analyzed. @*Results@#A total of 2,195 episodes were identified during the 25-year period between 1996 and 2020. S. pneumoniae (42.4%), S. aureus (22.1%), and Salmonella species (21.0%) were common in children 3 to 59 months of age. In children ≥ 5 years of age, S. aureus (58.1%), followed by Salmonella species (14.8%) and S. pneumoniae (12.2%) were common. Excluding the year 2020, there was a trend toward a decrease in the relative proportions of S. pneumoniae (rs = −0.430, P = 0.036), H. influenzae (rs = −0.922, P 3 months of age. These findings can be used as the baseline data to navigate the trend in the epidemiology of pediatric IBI in the post COVID-19 era.

Comparison of Antibody Response Elicited by ChAdOx1 and BNT162b2 COVID-19 Vaccine

Background@#ChAdOx1 and BNT162b2 vaccines are currently commonly used against coronavirus disease 2019 worldwide. Our study was designed to determine the serostatus and relative levels of anti-S and neutralizing antibodies in patients who were administered either ChAdOx1 or BNT162b2 vaccine. In addition, we investigated whether the antibody response to each vaccine differed according to sex and age. @*Methods@#Healthcare workers (HCWs) at a general hospital who were vaccinated with two doses of either ChAdOx1 or BNT162b2 were invited to participate in this prospective cohort study. Blood samples of HCWs vaccinated with both ChAdOx1 doses over a period of 12 weeks were collected at weeks 4 and 8 post first vaccination and 2 weeks post second vaccination. Blood samples of HCWs vaccinated with BNT162b2 were collected in the third week after the first dose, and the second dose was then administered on the same day; two weeks post second dose (5 weeks after the first dose), blood samples were collected to assess the antibody response. The titers of anti-S antibodies against the severe acute respiratory syndrome coronavirus 2 spike (S) protein receptor-binding domain and the neutralizing antibodies in the collected blood were evaluated. @*Results@#Of the 309 HCWs enrolled in the study, 205 received ChAdOx1 and 104 received BNT162b2. Blood samples from participants receiving either the ChAdOx1 or BNT162b2 vaccine exhibited substantial anti-S and neutralizing antibody seropositivity subsequent to the second dose. All participants (100%) from both vaccine groups were seropositive for anti-S antibody, while 98% (201/205) of ChAdOx1-vaccinated individuals and 100% (104/104) of BNT162b2-vaccinated individuals were seropositive for neutralizing antibodies.The median levels of anti-S and neutralizing antibodies were significantly higher in the BNT162b2-vaccinated group than the ChAdOx1-vaccinated group; in particular, anti-S antibody titers of 1,020 (interquartile range, 571.0–1,631.0) U/mL vs. 2,360 (1,243–2,500) U/mL, P < 0.05, were recorded for the ChAdOx1 and BNT162b2 groups, respectively, and neutralizing antibody titers of 85.0 (65.9–92.1%) vs. 95.8 (94.4–96.6%), P < 0.05, were recorded for the ChAdOx1 and BNT162b2 groups, respectively. In the ChAdOx1 vaccine group, the neutralizing antibody level was significantly higher in women than in men (85.7 [70.3–92.5%] vs. 77.7 [59.2–91.0%], P < 0.05); however, the neutralizing antibody titer in the BNT162b2 vaccine group did not vary between the two sexes (95.9 [95.2–96.6%] vs. 95.2 [93.5–96.3%], P = 0.200). Analysis of the correlation of antibody profiles with age revealed that the levels of anti-S antibodies and signal inhibition rate (SIR) of neutralizing antibodies decreased significantly with age. @*Conclusion@#Both the ChAdOx1- and BNT162b2-vaccinated groups showed high seropositivity for anti-S and neutralizing antibodies. The SIR of neutralizing antibodies in the ChAdOx1 vaccine group was higher in women than in men. Enhanced antibody responses were observed in participants vaccinated with BNT162b2 compared to those vaccinated with the ChAdOx1 vaccine.

Reactogenicity after the first and second doses of BNT162b2 mRNA coronavirus disease vaccine: a single-center study

Purpose@#This study was conducted to determine differences in adverse events associated with the first and second doses of the BNT162b2 coronavirus disease 2019 vaccine based on the age and sex of recipients. @*Materials and Methods@#An online survey on the post-vaccination adverse events of healthcare workers was conducted from March 2021 to April 2021. The differences in the types of adverse events, including severity, onset time, and duration of symptoms, and how the adverse events were dealt with by the patient were analyzed based on the age and sex. The profiles of adverse events were compared after the first and second vaccination doses. @*Results@#Among the 131 participants who participated in the online survey out of 208 vaccine recipients, 43 and 80 recipients of the BNT162b2 vaccine experienced adverse events after the first and second dose, respectively. No sex-related differences were observed in the profiles of adverse events in vaccinated recipients. The overall frequency of adverse events did not differ based on age after the first dose. After the second dose, the frequency of adverse events, including both local and systemic reactions was significantly higher in the younger age group than in the older age group. @*Conclusion@#The BNT162b2 vaccine resulted in a higher frequency of adverse events after the second dose than after the first dose especially in the younger age group; however, no sex-related differences associated with these adverse events were observed.

SARS-CoV-2 Antibody Response to the BNT162b2 mRNA Vaccine in Persons with Past Natural Infection

There are still no agreed guidelines on the vaccination of coronavirus disease 2019 (COVID-19) for previously infected patients. Here, we present two seropositive healthcare workers (HCWs) working in an isolation ward who recovered from COVID-19 in April 2020 and got vaccinated with BNT162b2 vaccine in March 2021. We have assessed the clinical course, vaccine-related adverse events, and antibody response after natural infection and after first and second dose vaccination. One of the two HCWs was asymptomatic during quarantine, but the other had mild upper respiratory infection symptoms 1 day before admission, and the symptoms continued for 9 days. There was no pneumonic infiltration in chest X-ray in both patients, and no COVID-19 specific treatment was administered.Total immunoglobulin antibody and neutralizing antibody to anti-spike protein receptorbinding domain of severe acute respiratory syndrome coronavirus 2 were confirmed to be present in both HCWs in blood tests performed at 2 weeks and 4 weeks after discharge.Antibody response to mRNA vaccination showed marked elevation after the first vaccination, which was 30–40 times higher than that of antibody titer after natural infection in each patient (83.2 U/mL vs. > 2,500 U/mL in patient 1; 61.6 U/mL vs. > 2,500 U/mL in patient 2).Signal inhibition rate of neutralizing antibodies was also increased to over 97%. Due to this increased effect, there was little difference in antibody levels after the first and second dose. Both patients 1 and 2 suffered more from adverse vaccine reactions after the second vaccination than from COVID-19 symptoms.

Report of the Korean Society of Infectious Diseases Roundtable Discussion on Responses to the Measles Outbreaks in Korea in 2019

During the 2019 domestic measles outbreak in Korea, measles occurred in healthcare workers with two doses of the measles, mumps and rubella vaccine, and the strict application of the Occupational Safety and Health Act required medical institutions to identify healthcare workers' immunity to measles and vaccinate the susceptible pockets. In response to the frontline medical institutions' request to review the measles recommendations and guidelines, the Korean Society of Infectious Diseases held a roundtable discussion on the causes of measles outbreak, timing of vaccinations, antibody tests, and booster vaccinations for healthcare workers, and financial support from the government and municipality as well as response strategies against the outbreak in healthcare settings. In Korea, the seroprevalence of measles is decreasing in the vaccine-induced immunity group during the maintenance of measles elimination over several years. The susceptible group against measles is in their 20s and 30s, and this may be because of waning immunity rather than nonresponse considering Korea's vaccine policy. The risk of measles nosocomial infection from community increases as these susceptible pockets actively engage in medical institutions.Thus, data on the immunity of low seroprevalence group in Korea are needed, further discussion is needed on the booster vaccination based on the data. Especially, antibody testing and vaccination in healthcare workers may be necessary to prevent the spread of measles in medical insutitutions, and further discussion is needed regarding specific testing methods, and the timing and frequency of test and vaccination.

SARS-CoV-2 Antibody Response to the BNT162b2 mRNA Vaccine in Persons with Past Natural Infection

There are still no agreed guidelines on the vaccination of coronavirus disease 2019 (COVID-19) for previously infected patients. Here, we present two seropositive healthcare workers (HCWs) working in an isolation ward who recovered from COVID-19 in April 2020 and got vaccinated with BNT162b2 vaccine in March 2021. We have assessed the clinical course, vaccine-related adverse events, and antibody response after natural infection and after first and second dose vaccination. One of the two HCWs was asymptomatic during quarantine, but the other had mild upper respiratory infection symptoms 1 day before admission, and the symptoms continued for 9 days. There was no pneumonic infiltration in chest X-ray in both patients, and no COVID-19 specific treatment was administered.Total immunoglobulin antibody and neutralizing antibody to anti-spike protein receptorbinding domain of severe acute respiratory syndrome coronavirus 2 were confirmed to be present in both HCWs in blood tests performed at 2 weeks and 4 weeks after discharge.Antibody response to mRNA vaccination showed marked elevation after the first vaccination, which was 30–40 times higher than that of antibody titer after natural infection in each patient (83.2 U/mL vs. > 2,500 U/mL in patient 1; 61.6 U/mL vs. > 2,500 U/mL in patient 2).Signal inhibition rate of neutralizing antibodies was also increased to over 97%. Due to this increased effect, there was little difference in antibody levels after the first and second dose. Both patients 1 and 2 suffered more from adverse vaccine reactions after the second vaccination than from COVID-19 symptoms.

Report of the Korean Society of Infectious Diseases Roundtable Discussion on Responses to the Measles Outbreaks in Korea in 2019

During the 2019 domestic measles outbreak in Korea, measles occurred in healthcare workers with two doses of the measles, mumps and rubella vaccine, and the strict application of the Occupational Safety and Health Act required medical institutions to identify healthcare workers' immunity to measles and vaccinate the susceptible pockets. In response to the frontline medical institutions' request to review the measles recommendations and guidelines, the Korean Society of Infectious Diseases held a roundtable discussion on the causes of measles outbreak, timing of vaccinations, antibody tests, and booster vaccinations for healthcare workers, and financial support from the government and municipality as well as response strategies against the outbreak in healthcare settings. In Korea, the seroprevalence of measles is decreasing in the vaccine-induced immunity group during the maintenance of measles elimination over several years. The susceptible group against measles is in their 20s and 30s, and this may be because of waning immunity rather than nonresponse considering Korea's vaccine policy. The risk of measles nosocomial infection from community increases as these susceptible pockets actively engage in medical institutions.Thus, data on the immunity of low seroprevalence group in Korea are needed, further discussion is needed on the booster vaccination based on the data. Especially, antibody testing and vaccination in healthcare workers may be necessary to prevent the spread of measles in medical insutitutions, and further discussion is needed regarding specific testing methods, and the timing and frequency of test and vaccination.

Catastrophic Antiphospholipid Syndrome Associated with Systemic Lupus Erythematosus Successfully Treated with Rituximab: A Case Report

The catastrophic variant of antiphospholipid syndrome (APS) is a very rare and life-threatening condition of APS. This condition is characterized by thrombosis in multiple organs within a short period of time in the presence of positive antiphospholipid antibodies (aPL). Over the past few decades, considerable progress has been made in the treatment of patients with catastrophic APS; however, the mortality rate still remains very high. Although some cases of rituximab treatment in patients with catastrophic APS have been reported, there is no clear treatment protocol. A 14-year-old girl with systemic lupus erythematosus was diagnosed with catastrophic APS. She received several medications: corticosteroids, intravenous immunoglobulin, and plasmapheresis with anticoagulants. Unfortunately, she did not improve, and rituximab was started with four courses. After the rituximab treatment, she did not experience further thrombotic events during the follow up. This paper reports a pediatric case of catastrophic APS treated successfully with rituximab in Korea.

Long Term Safety and Efficacy of Etanercept in Juvenile Idiopathic Arthritis in a Single Center

OBJECTIVE: Our aim was to investigate the long term safety and efficacy of etanercept in children with juvenile idiopathic arthritis (JIA). METHODS: The study subjects were the 90 JIA patients treated with etanercept in the Department of Pediatrics, Hallym University Medical Center between January 2004 and December 2017. We retrospectively reviewed their medical records for age at diagnosis, duration of etanercept treatment, number of active joints, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and adverse events during treatment. RESULTS: Among the 90 patients, 38 (42.0%) were male and 52 (58.0%) were female; 15 (16.7%) had systemic onset, 41 (45.6%) had extended oligoarticular, 14 (15.6%) had rheumatoid factor-positive polyarticular, 18 (20.0%) had rheumatoid factor-negative polyarticular, and 2 (2.1%) had enthesitis-related arthritis. The median age at the start of etanercept treatment was 9 years (range, 3~18 years), and the median duration of etanercept treatment was 6 years (range, 0.5~13 years). The median number of active joints decreased from 9 to 0 after 6 months of etanercept treatment. The median CRP and ESR were within normal range after 3 months of treatment. Six patients experienced recurrence, 9 switched to other medications and 3 discontinued etanercept. Of the 14 reported adverse events, 1 was serious, and there were no tuberculosis infections or malignancies. CONCLUSION: Long-term treatment with etanercept is efficacious and safe for children with JIA. However, those with the systemic onset subtype appear to have low drug survival rate compared to those with other types of JIA.

Erratum: Addition of a Co-Author: Etiology of Invasive Bacterial Infections in Immunocompetent Children in Korea (2006–2010): a Retrospective Multicenter Study

The authors regret that one co-author (Kyung-Hyo Kim) was missing in the article.

Prevalence of Lower Bone Mineral Density and Its Associated Factors in Korean Children and Adolescents with Juvenile Idiopathic Arthritis

OBJECTIVE: This study examined the prevalence of low-bone mineral density (BMD) and its associated factors in Korean children and adolescents with juvenile idiopathic arthritis (JIA). METHODS: Thirty-nine patients with JIA were included in this cross-sectional study. The patients were examined for their bone age (BA) and bone mineral density (BMD). The BMD was measured using dual-energy X-ray absorptiometry on the lumbar spine. Each BMD value was converted to a Z-score by comparing the reference values of the healthy control group in terms of the age and sex of each patient, which was measured using the same device. A Z-score of less than −2.0 was defined as a low BMD. Laboratory tests were performed to detect the serum calcium, phosphorus, alkaline phosphatase, and 25-hydroxyvitamin D levels. RESULTS: The mean age at the time of the examination was 12.2±3.6 years, and the study comprised a total of 39 patients (16 males, 23 females). Patients with systemic JIA had a lower BMD, which was calculated based on the CA, BA, and HA, than those with non-systemic JIA (P=0.020, P=0.049, and P=0.024, respectively); the corticosteroid user group also showed a lower BMD, which had been calculated based on the CA, BA, and HA, than the corticosteroid non-user group (p=0.002, p=0.022, and p=0.188, respectively). CONCLUSION: This study suggests that JIA patients have a lower BMD than control subjects. Therefore, treatment, and education are warranted while treating patients with JIA, particularly those requiring oral corticosteroids or those with systemic JIA and appropriate laboratory tests.

New Provisional Classification of Juvenile Idiopathic Arthritis Applying Rheumatoid Factor and Antinuclear Antibody

OBJECTIVE: Previous classification systems for juvenile idiopathic arthritis (JIA) were based on the number of joints involved and did not categorize homogenous disease entities. Therefore, JIA patients were reclassified retrospectively by applying rheumatoid factor (RF) and antinuclear antibody (ANA), which have been proven to constitute a homogenous disease entity. METHODS: The medical records of JIA patients were investigated retrospectively and reclassified into six categories using the new provisional classification. The nomenclature was based on Dr. Martini's proposal in the 23rd European Paediatric Rheumatology Congress (2016) at Genoa, Italy. New categories included systemic JIA (sJIA), RF-positive JIA (RF-JIA), early-onset ANA-positive JIA (eoANA-JIA), enthesitis/spondylitis-related JIA (ESR-JIA), “other JIA”, and “unclassified JIA”. RESULTS: Of a total of 262 JIA patients, 71 (27.1%) were reclassified as sJIA, 31 (11.8%) as RF-JIA, 22 (8.4%) as eoANA-JIA, 63 (24.0%) as ESR-JIA, 65 (24.8%) as “other JIA”, and 10 (3.8%) as “unclassified JIA”. A comparison of RF-JIA, eoANA-JIA, and ESR-JIA revealed significant differences in the gender ratio, age of disease onset, and the cumulative number and type of joints involved among the three groups. “Other JIA” comprised a significant proportion (24.8%) and warrants the need for further classification. The characteristics of the RF-positive patients were comparable to those of the anti-cyclic citrullinated peptide antibody-positive patients. The ANA positivity was lower (28.2%) than that in Western studies but showed similar clinical features. CONCLUSION: This is the first study applying RF and ANA to classify JIA without considering the joint counts. The six new categories include sJIA, RF-JIA, eoANA-JIA, ESR-JIA, “other JIA,” and “unclassified JIA”.

Prevalence, Risk Factors, and Expression of Human Leukocyte Antigen-DRB1 in Juvenile Idiopathic Arthritis-associated Uveitis

OBJECTIVE: This study investigated the prevalence and risk factors of juvenile idiopathic arthritis (JIA)-associated uveitis (JIA-U) in a pediatric tertiary center in Korea. In addition, this study examined whether a specific HLA-DRB1 allele could be a predictive risk factor of uveitis in JIA. METHODS: The pediatric rheumatology and ophthalmology medical records for JIA between March 2006 and March 2016 were analyzed retrospectively. A total of 233 were enrolled in this study. RESULTS: Of 233 patients, 31 developed uveitis (13.3%): 14 oligoarticular, three polyarticular, six systemic, seven enthesitis-related, and one undifferentiated-type JIA. In oligoarticular JIA, 26.4% developed uveitis. The percentage of females with JIA-U was 54.8%, and the median age of the onset of JIA was 7.02 years in JIA-U. Antinuclear antibody (ANA) positivity in oligoarticular JIA-U was 57.1%. Of the 31 JIA-U cases, 26 (83.9%) were clinically asymptomatic when diagnosed. The allele frequency of HLA-DRB1*09 of the total JIA-U was higher than that of JIA without uveitis. HLA-DRB1*09 and HLA-DRB1*12 were higher in oligoarticular JIA-U than in JIA without uveitis. CONCLUSION: Korean JIA-U has different features from JIA-U in Western countries. The sex ratio and age of JIA onset showed no significant differences in Korean JIA-U. The ANA positivity was more common in JIA-U than in JIA without uveitis only in oligoarticular type JIA. These differences might be due to genetic factors, particularly HLA-DRB1. These results suggest HLA-DRB1*09 and HLA-DRB1*12 in oligoarticular JIA to be risk factors for JIA-U in Korea. This is the first study to analyze the association between HLA-DRB1 and JIA-U in Korea.

Etiology of Invasive Bacterial Infections in Immunocompetent Children in Korea (2006–2010): a Retrospective Multicenter Study

BACKGROUND: Invasive bacterial infections in apparently immunocompetent children were retrospectively analyzed to figure causative bacterial organisms in Korea. METHODS: A total of 947 cases from 25 university hospitals were identified from 2006 to 2010 as a continuance of a previous 10-year period study from 1996 to 2005. RESULTS: Escherichia coli (41.3%), Streptococcus agalactiae (27.7%), and Staphylococcus aureus (27.1%) were the most common pathogens in infants < 3 months of age. S. agalactiae was the most prevalent cause of meningitis and pneumonia and E. coli was the major cause of bacteremia without localizing signs in this group. In children 3 to 59 months of age, Streptococcus pneumoniae (54.2%), S. aureus (20.5%), and Salmonella spp. (14.4%) were the most common pathogens. S. pneumoniae was the leading cause of pneumonia (86.0%), meningitis (65.0%), and bacteremia without localizing signs (49.0%) in this group. In children ≥ 5 years of age, S. aureus (62.8%) was the predominant pathogen, followed by Salmonella species (12.4%) and S. pneumoniae (11.5%). Salmonella species (43.0%) was the most common cause of bacteremia without localizing signs in this group. The relative proportion of S. aureus increased significantly over the 15-year period (1996–2010) in children ≥ 3 months of age (P < 0.001), while that of Haemophilus influenzae decreased significantly in both < 3 months of age group (P = 0.036) and ≥ 3 months of age groups (P < 0.001). CONCLUSION: S. agalactiae, E. coli, S. pneumoniae, and S. aureus are common etiologic agents of invasive bacterial infections in Korean children.

Acute Appendicitis in Children and Adolescents: Factors Associated with Perforation and the Causative Organism

PURPOSE: This study aimed to determine which factors are related to perforated appendicitis. We also conducted a survey to identify the causative organism. METHODS: From January 2011 to December 2014, 569 pediatric patients (322 male) younger than 19 years old who underwent an appendectomy due to acute appendicitis at Hallym University Sacred Heart Hospital were enrolled. Patients' medical records were reviewed retrospectively to determine their clinical manifestations, laboratory and imaging results, and pathogens. RESULTS: About 127 patients (22%) had perforated appendicitis. The rate of perforated appendicitis in preschool, late childhood, and adolescent ages were 50%, 27%, and 16.8%, respectively. The risk factors of perforation were high C-reactive protein levels and the presence of appendiceal fecalith (P <0.001). Of the 24 samples of peritoneal fluid and periappendiceal pus that were collected intraoperatively, 16 were culture positive. The most common pathogen was Escherichia coli (n=10), and others were Pseudomonas aeruginosa , Streptococcus spp., and Staphylococcus spp. CONCLUSIONS: The perforation rate of appendicitis among patients younger than 5 years old was 50%, and this decreased in proportion with age. Clinicians should be aware of the possibility of perforation when patients with appendicitis have high C-reactive protein levels or the presence of appendiceal fecalith on imaging.

The Efficacy of Rapid Antigen Tests for Detection of Seasonal Influenza Virus

PURPOSE: This study aimed to examine the accuracy of rapid influenza diagnostic tests (RIDT) in children with an influenza-like illness and to evaluate factors associated with greater accuracy. METHODS: Pediatric patients, who visited Hallym University Sacred Heart Hospital with an influenza-like illness between June 2011 and May 2016, were enrolled in this study. We tested 798 samples using a real-time polymerase chain reaction (PCR) for respiratory viruses and compared the results with rapid influenza tests. RESULTS: In comparison with the results of the multiplex PCR, the positive agreement rates of RIDT for influenza A and B virus were 75.7% and 60.0%, respectively. The performance of RIDT varied according to days after fever onset. The positive agreement rates of RIDT for influenza A and B tests, performed within 4 days of fever onset, were 77.6% and 73.2%, but the rates for tests performed more than 5 days after fever onset were 66.7% and 21.4%, respectively. CONCLUSIONS: The RIDT is a quick and simple aid to diagnosis, but is less sensitive than the labeled sensitivity. Moreover, test performance varied according to days after fever onset. Test specimens for RIDT should be collected as soon as possible after the onset of symptoms (less than 4 days).

Comparison of Cervical-lymph-node-first Presentation of Kawasaki Disease and Typical Kawasaki Disease

PURPOSE: The diagnosis of Kawasaki disease depends on clinical symptoms, which makes it difficult to diagnose early in patients with only cervical lymphadenopathy. The purpose of this study is to understand the clinical characteristics of cervical-lymph-node-first presentation of Kawasaki disease and compare them with those of typical Kawasaki disease. METHODS: We surveyed 283 patients who were admitted to Hallym Sacred Heart Hospital and were diagnosed with Kawasaki disease from January 2012 to December 2014. The patients were divided into two groups: cervical-lymph-node-first presentation of Kawasaki disease (LKD, N=24) and typical Kawasaki disease (KD, N=259). The medical records were retrospectively reviewed. RESULTS: The mean age of the LKD group was higher than that of the KD group (P=0.04). At admission, the LKD patients had on average 1.62 out of 5 symptoms, whereas the KD patients had 3.47. The time from fever to diagnosis and administration of IV immunoglobulin was longer in the LKD group than in the KD group (P<0.001). The mean C-reactive protein of the LKD group was higher than that of the KD group (P=0.01). There were no statistical differences in the presence of coronary artery complications between the two groups at two weeks or at two months after diagnosis (P=0.52, P=0.08). CONCLUSIONS: The Kawasaki disease patients with fever and cervical lymphadenopathy usually do not present obvious clinical symptoms, which makes it hard to diagnose in the early phase of disease. Clinician must pay attention when examining these patients.

Early Changes in the Serotype Distribution of Invasive Pneumococcal Isolates from Children after the Introduction of Extended-valent Pneumococcal Conjugate Vaccines in Korea, 2011-2013

This study was performed to measure early changes in the serotype distribution of pneumococci isolated from children with invasive disease during the 3-year period following the introduction of 10- and 13-valent pneumococcal conjugate vaccines (PCVs) in Korea. From January 2011 to December 2013 at 25 hospitals located throughout Korea, pneumococci were isolated among children who had invasive pneumococcal disease (IPD). Serotypes were determined using the Quellung reaction, and the change in serotype distribution was analyzed. Seventy-five cases of IPD were included. Eighty percent of patients were aged 3-59 months, and 32% had a comorbidity that increased the risk of pneumococcal infection. The most common serotypes were 19A (32.0%), 10A (8.0%), and 15C (6.7%). The PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, 23F, and 6A) accounted for 14.7% of the total isolates and the PCV13 minus PCV7 types (1, 3, 5, 7F and 19A) accounted for 32.0% of the total isolates. Serotype 19A was the only serotype in the PCV13 minus PCV7 group. The proportion of serotype 19A showed decreasing tendency from 37.5% in 2011 to 22.2% in 2013 (P = 0.309), while the proportion of non-PCV13 types showed increasing tendency from 45.8% in 2011 to 72.2% in 2013 (P = 0.108). Shortly after the introduction of extended-valent PCVs in Korea, serotype 19A continued to be the most common serotype causing IPD in children. Subsequently, the proportion of 19A decreased, and non-vaccine serotypes emerged as an important cause of IPD. The impact of extended-valent vaccines must be continuously monitored.

Human Leukocyte Antigen B27 and Juvenile Idiopathic Arthritis and Classification of Juvenile Spondyloarthropathies by the Assessment of SpondyloArthritis International Society Criteria

OBJECTIVE: We examined the clinical relationship between human leukocyte antigen B27 (HLA-B27) and juvenile idiopathic arthritis (JIA). Additionally, we assessed the usefulness of the Assessment of SpondyloArthritis International Society (ASAS) criteria for diagnosing juvenile spondyloarthropathies (SpA). METHODS: We retrospectively reviewed medical records of 239 patients with JIA classified according to the International League of Associations for Rheumatology (ILAR) classification to analyze the features of the joint involvement site. Results were correlated with the presence of HLA-B27. After that, we classified the 239 JIA patients according to the ASAS criteria to diagnose juvenile SpA. The relationship between the ASAS criteria and a diagnosis of juvenile SpA was analyzed by a chi-squared test. RESULTS: Back pain was associated with HLA-B27 in boys (p=0.002) but not in girls (p=0.616). In both sexes, involvement of the small joints in the lower extremities was highly associated with HLA-B27 (p=0.001 for boys, p=0.021 for girls). In addition, HLA-B27 was associated with enthesitis (p=0.004 for boys, p=0.021 for girls). Eighty-seven (36.4%) patients with JIA fulfilled the ASAS criteria; 2 (0.8%) had axial SpA and 85 (35.6%) had peripheral SpA. HLA-B27 was the most significant factor for diagnosing juvenile SpA (sensitivity 80%, specificity 99.31%, positive likelihood ratio, 116). CONCLUSION: The ILAR criteria have some weaknesses for diagnosing HLA-B27-positive JIA patients in early stages. The use of the ASAS criteria for juvenile patients will enable pediatric rheumatologists to diagnose juvenile SpA patients earlier.

An Unusual Cause of Acute Maxillary Sinusitis in a 9-year-old Child: Odontogenic Origin of Infected Dentigerous Cyst with Supernumerary Teeth

Acute maxillary sinusitis is a common disorder affecting children. Untreated acute sinusitis can develop into chronic sinusitis, and complications, such as orbital cellulitis or abscess, can occur. Maxillary sinusitis of odontogenic origin is not a well-recognized condition and is frequently missed in children. As an odontogenic source of sinusitis, the dentigerous cyst is one of the most prevalent types of odontogenic cysts, and it is associated with the crown of an unerupted or developing tooth. This report concerns a nine-year-old boy who was diagnosed with maxillary sinusitis originating from a dentigerous cyst with supernumerary teeth. The boy visited our pediatric clinic presenting with rhinorrhea and nasal obstruction and was initially diagnosed with maxillary sinusitis only. With antibiotic treatment, his symptoms seemed to improve, but after 2 months, he came to our clinic with left facial swelling with persistent rhinorrhea and nasal obstruction. Radiographic examinations of the sinuses were performed, and he was diagnosed with maxillary sinusitis originating from a dentigerous cyst with supernumerary teeth. After a surgical procedure involving the removal of the dentigerous cyst with supernumerary teeth, the symptoms of sinusitis gradually diminished. There are only very few cases in the pediatric medical literature that remind us that odontogenic origin can cause maxillary sinusitis in children. Our patient can act as a reminder to general pediatricians to include dentigerous cysts in the differential diagnosis of maxillary sinusitis.