A Report on a Nationwide Surveillance System for Pediatric Acute Hepatitis of Unknown Etiology in Korea.

BACKGROUND: Several cases of pediatric acute hepatitis of unknown etiology related to adenoviral infections have been reported in Europe since January 2022. The aim of this study was to compare the incidence, severity, possible etiology, and prognosis of the disease with those in the past in Korea. METHODS: The surveillance group collected data between May and November 2022 using a surveillance system. Acute hepatitis of unknown etiology was defined in patients aged < 16 years with a serum transaminase level > 500 IU/L, not due to hepatitis A-E or other underlying causes. For comparison, data from 18 university hospitals were retrospectively collected as a control group between January 2021 and April 2022. RESULTS: We enrolled 270 patients (mean age, 5 years). The most common symptom was fever. However, the incidence was similar between 2021 and 2022. Liver function test results, number of patients with acute liver failure (ALF), liver transplantation (LT), death, and adenovirus detection rates did not differ between the two groups. None of the adenovirus-positive patients in either group experienced ALF, LT, or death. In the surveillance group, adenovirus-associated virus-2 was detected in four patients, one of whom underwent LT. Patients with an unknown etiology showed significantly higher bilirubin levels, a lower platelet count, and a higher LT rate than patients with a possible etiology. CONCLUSION: The incidence of pediatric acute hepatitis of unknown etiology and adenovirus detection rate have not increased in Korea.

Recommendation for use of diphtheria and tetanus toxoids and acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b conjugate, and hepatitis B vaccine in infants.

In April 2020, the Ministry of Food and Drug Safety licensed a hexavalent combined diphtheria and tetanus toxoids and acellular pertussis (DTaP), inactivated poliovirus (IPV), Haemophilus influenzae type b (Hib) conjugated to tetanus protein, and hepatitis B (HepB) (recombinant DNA) vaccine, DTaP-IPV-Hib-HepB (Hexaxim, Sanofi Pasteur), for use as a 3-dose primary series in infants aged 2, 4, and 6 months. The DTaP-IPV-Hib-HepB vaccine is highly immunogenic and safe and provides a long-term immune response based on studies performed in a variety of settings in many countries, including Korea. This report summarizes the Committee on Infectious Diseases of the Korean Pediatric Society guidelines for the use of this newly introduced hexavalent combination vaccine.

Comparison of the Immunogenicity and Safety of Three Enhanced Inactivated Poliovirus Vaccines from Different Manufacturers in Healthy Korean Infants: A Prospective Multicenter Study.

The enhanced inactivated poliovirus vaccine was first introduced in 2002, and several inactivated poliovirus vaccines are licensed in Korea. Reliable data by a prospective study on the immunogenicity and safety of the inactivated poliovirus vaccines in Korean infants are required. Normal healthy infants aged 6-12 weeks received three doses of the vaccine (IPVAX™, Imovax Polio™ or Poliorix™) in intervals of 2 months. Neutralizing antibody (NTAb) titers were measured before and 4-6 weeks after three-dose primary vaccination. Immunogenicity was evaluated by seroconversion rates and geometric mean titers obtained by analyzing NTAb titers. Local and systemic adverse events were recorded during 7 days after each vaccination. A total of 150 infants were included: 40 in IPVAX™, 52 in Imovax Polio™, and 58 in Poliorix™. The seroconversion rates for the group vaccinated with IPVAX™ were 100% in types 1, 2 and 3, while those of Imovax Polio™ were 98.1%, 96.2%, 96.2% and those of Poliorix™ were 98.3%, 100%, 100%, respectively. In all groups, injection site redness and irritability were the most common local and systemic adverse events. Neither serious adverse events nor adverse events above grade 2 were reported throughout the study. The currently used inactivated poliovirus vaccines was demonstrated to be safe and immunogenic in healthy Korean infants.

A Randomized, Double-blind, Active-controlled Phase III Trial of a Cell Culture-derived Quadrivalent Inactivated Influenza Vaccine in Healthy South Korean Children and Adolescents 6 Months to 18 Years of Age.

BACKGROUND: Cell culture-derived influenza vaccines have several important advantages over egg-based influenza vaccines. The quadrivalent influenza vaccine may offer broader protection against seasonal influenza than trivalent influenza vaccine by containing 1 more B strain. The purpose of this study was to evaluate the immunogenicity and safety of NBP607-QIV, a novel cell culture-derived inactivated quadrivalent influenza vaccine (cIIV4), in children and adolescents. METHODS: This phase III, randomized, double-blind, multicenter trial in children/adolescents (6 mo to 18 yr) was conducted in South Korea during 2014-2015 season. Subjects were randomized 4:1 to receive either NBP607-QIV or control inactivated trivalent influenza vaccine. Hemagglutination inhibition antibody titers were assessed in prevaccination and 28 days postvaccination sera. Safety data were collected for up to 6 months postvaccination. RESULTS: A total of 454 participants completed the study. Three-hundred sixty-six subjects received cIIV4 and 88 subjects received inactivated trivalent influenza vaccine. Overall, NBP607-QIV met the immunogenicity criteria of Committee for Medicinal Products for Human Use for each of the 4 strains. Between the NBP607-QIV and control groups, immunogenicity endpoints were comparable. Participants younger than 3 years of age had lower immunologic responses to 2 influenza B strains in both NBP607-QIV and control group. No deaths, vaccine-related serious adverse events (AEs) or withdrawals because of AEs were reported. The solicited AEs reported were generally of mild intensity. CONCLUSIONS: NBP607-QIV, a novel cIIV4, showed good immunogenicity to all 4 influenza strains and had tolerable safety profiles in children and adolescents. Moreover, NBP607-QIV was more immunogenic against influenza B compared with the control, an egg-based subunit vaccine.

Recommended immunization schedule for children and adolescents: Committee on Infectious Diseases of the Korean Pediatric Society, 2018.

The Committee on Infectious Diseases of the Korean Pediatric Society recommended immunization schedule for children and adolescents aged 18 years or younger in the 9th (2018) edition of Immunization guideline. This report provides the revised recommendations made by the committee and summarizes several changes from the 2015 guideline. National immunization program (NIP) launched a human papillomavirus (HPV) immunization for girls aged 12 years in 2016. NIP has also expanded age indication for inactivated influenza vaccine (IIV) to 12 years of age in the 2018-2019 season. Quadrivalent IIVs with a full dose (0.5 mL) are approved for all children of 6 months or older. Recommendations of live attenuated influenza vaccine were removed. For inactivated Japanese encephalitis vaccine, first 2 doses are considered as the primary series. Recommendations for use of newly introduced vaccines (diphtheria-tetanus-acellular pertussis/inactivated poliovirus/Haemophilus influenzae type b, 9-valent HPV, new varicella vaccine, new quadrivalent IIV, and attenuated oral typhoid vaccine) were added. Lastly, monitoring system for adverse events following immunization was updated. Other changes can be found in the 9th edition of Immunization guideline in detail.

Immunogenicity and safety of a combined DTPa-IPV/Hib vaccine administered as a three-dose primary vaccination course in healthy Korean infants: phase III, randomized study.

We assessed the immunogenicity and safety of a three-dose primary vaccination schedule with the combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in Korean infants. In this phase III open-label, multicenter study (NCT01309646), healthy infants aged 42-69 days (randomized 1:1) received three doses of either pentavalent DTPa-IPV/Hib (DTPa-IPV/Hib group) or DTPa-IPV and Hib vaccines administered separately (DTPa-IPV+Hib group) at 2, 4, 6 months of age. The primary objective was to demonstrate non-inferiority of DTPa-IPV/Hib compared to DTPa-IPV+Hib vaccines in terms of immune responses to all vaccine antigens, 1 month post-dose 3. Solicited symptoms (local and general) were recorded during 4 days, and unsolicited adverse events (AEs) during 31 days, after each vaccination. Serious AEs (SAEs) were recorded throughout the study duration. The immunogenicity of the pentavalent DTPa-IPV/Hib vaccine was non-inferior compared to concomitant administration of DTPa-IPV+Hib vaccines. One month post-dose 3, nearly all infants had antibody levels above the seroprotective thresholds for anti-diphtheria toxoid, anti-tetanus toxoid, anti-polyribosyl-ribitol phosphate, and anti-poliovirus type 1, 2 and 3, and had antibody levels above the seropositive thresholds for anti-pertussis toxoid (PT), anti-filamentous hemagglutinin (FHA) and anti-pertactin (PRN) antibodies. A vaccine response for PT, FHA and PRN was observed in at least 96.7% of study participants. Anti-PRP geometric mean concentrations appeared lower for the DTPa-IPV/Hib group (8.456 µg/mL) than for the DTPa-IPV+Hib group (18.700 µg/mL). In both groups, the most common solicited symptoms were injection site redness and irritability. Fifty-seven SAEs were reported throughout the study; none were considered to be vaccination related.

CRISPR/Cas9-Mediated Gene Disruption Reveals the Importance of Zinc Metabolism for Fitness of the Dimorphic Fungal Pathogen Blastomyces dermatitidis.

Blastomyces dermatitidis is a human fungal pathogen of the lung that can lead to disseminated disease in healthy and immunocompromised individuals. Genetic analysis of this fungus is hampered by the relative inefficiency of traditional recombination-based gene-targeting approaches. Here, we demonstrate the feasibility of applying CRISPR/Cas9-mediated gene editing to Blastomyces, including to simultaneously target multiple genes. We created targeting plasmid vectors expressing Cas9 and either one or two single guide RNAs and introduced these plasmids into Blastomyces via Agrobacterium gene transfer. We succeeded in disrupting several fungal genes, including PRA1 and ZRT1, which are involved in scavenging and uptake of zinc from the extracellular environment. Single-gene-targeting efficiencies varied by locus (median, 60% across four loci) but were approximately 100-fold greater than traditional methods of Blastomyces gene disruption. Simultaneous dual-gene targeting proceeded with efficiencies similar to those of single-gene-targeting frequencies for the respective targets. CRISPR/Cas9 disruption of PRA1 or ZRT1 had a variable impact on growth under zinc-limiting conditions, showing reduced growth at early time points in low-passage-number cultures and growth similar to wild-type levels by later passage. Individual impairment of PRA1 or ZRT1 resulted in a reduction of the fungal burden in a mouse model of Blastomyces infection by a factor of ~1 log (range, up to 3 logs), and combined disruption of both genes had no additional impact on the fungal burden. These results underscore the utility of CRISPR/Cas9 for efficient gene disruption in dimorphic fungi and reveal a role for zinc metabolism in Blastomyces fitness in vivoIMPORTANCEBlastomyces is a human fungal pathogen that can cause serious, even fatal, lung infections. Genetic analysis of this fungus is possible but inefficient. We applied a recently developed gene editing technology, CRISPR/Cas9, to dramatically improve the efficiency with which gene disruptions are introduced into Blastomyces We used this system to disrupt genes involved in zinc uptake and found that this reduced the fitness of the fungus upon infection.

A Randomized, Double-blind, Active-controlled Clinical Trial of a Cell Culture-derived Inactivated Trivalent Influenza Vaccine (NBP607) in Healthy Children 6 Months Through 18 Years of Age.

BACKGROUND: Although a number of cell culture-derived influenza vaccines have been approved for use in adults, there have been few clinical trials of cell culture-derived seasonal influenza vaccines for young children. METHODS: We conducted a randomized, double-blind phase III clinical trial to evaluate the safety and immunogenicity of a cell culture-derived subunit trivalent inactivated influenza vaccine (NBP607, SK Chemicals Co., Ltd., Seongnam, Korea) in healthy children 6 months of age through 18 years. Subjects were randomized to receive either a study vaccine or an egg-based control vaccine. Antibody levels were measured by the hemagglutination inhibition assay, using cell-derived antigens. Solicited adverse events were assessed for 7 days after each injection. Serious adverse events were collected for 6 months after vaccination. RESULTS: A total of 374 participants completed the study. No deaths, vaccine-related serious adverse events or withdrawals resulting from adverse events were reported. Rates of solicited and unsolicited adverse events were similar in 2 groups. Overall, NBP607 met the immunogenicity criteria of the Committee for Proprietary Medicinal Products for the 3 influenza strains. Between the NBP607 group and the control group, immunogenicity endpoints were comparable. Participants younger than 3 years of age had lower immunologic responses against the influenza B virus in both the NBP607 group and the control group. CONCLUSIONS: The immunogenicity and safety were comparable between the NBP607 group and the control group. NBP607 is well tolerated and immunogenic in children 6 months of age through 18 years.

Ligation of Dectin-2 with a novel microbial ligand promotes adjuvant activity for vaccination.

The development of vaccines against fungi and other intracellular microbes is impeded in part by a lack of suitable adjuvants. While most current vaccines against infectious diseases preferentially induce production of antibodies, cellular immunity is essential for the resolution of fungal infections. Microbes such as fungi and Mycobacterium tuberculosis require Th17 and Th1 cells for resistance, and engage the C-type lectin receptors including Dectin-2. Herein, we discovered a novel Dectin-2 ligand, the glycoprotein Blastomyces Eng2 (Bl-Eng2). Bl-Eng2 triggers robust signaling in Dectin-2 reporter cells and induces IL-6 in human PBMC and BMDC from wild type but not Dectin-2-/- and Card9-/- mice. The addition of Bl-Eng2 to a pan-fungal subunit vaccine primed large numbers of Ag-specific Th17 and Th1 cells, augmented activation and killing of fungi by myeloid effector cells, and protected mice from lethal fungal challenge, revealing Bl-Eng2's potency as a vaccine adjuvant. Thus, ligation of Dectin-2 by Bl-Eng-2 could be harnessed as a novel adjuvant strategy to protect against infectious diseases requiring cellular immunity.

Immunogenicity and safety of a tetravalent measles-mumps-rubella-varicella vaccine: an open-labeled, randomized trial in healthy Korean children.

PURPOSE: This study (NCT00751348) evaluated the immunogenicity and safety of a combined measles-mumps-rubella-varicella (MMRV) vaccine compared to co-administration of measles-mumps-rubella and varicella (MMR+V) vaccines in Korean children during their second year of life. MATERIALS AND METHODS: Healthy children aged 11-24 months received one dose of MMRV or MMR+V. Antibody titers against measles, mumps and rubella were measured using enzyme-linked immunosorbent assay and against varicella using an immunofluorescence assay. Parents/guardians recorded adverse events in diary cards for up to 43 days post-vaccination. The primary objective was to demonstrate non-inferiority of MMRV to MMR+V for all antigens in terms of seroconversion rates (SCRs), defined as a group difference with a lower limit of the 95% confidence interval (CI)>-10%. RESULTS: Of 474 subjects enrolled, 458 (MMRV, 301; MMR+V, 157) were included in the according-to-protocol cohort. For measles (98.0% vs. 99.4%), rubella (99.7% vs. 100%) and varicella (98.9% vs. 100%) SCRs, the lower limits of the 95% CIs for group differences were greater than -10%; however, for mumps SCRs (88.8% vs. 94.2%), it was -10.40%. The primary objective of non-inferiority in mumps SCRs was therefore not met, although the observed group difference in a post-hoc analysis of anti-mumps antibodies using a plaque reduction neutralization assay was 0.39% with a 95% CI lower limit of -4.03%. Adverse events occurred at comparable frequencies for both groups, except for more frequent fever in MMRV recipients. CONCLUSION: Based on the pre-specified non-inferiority criterion, SCRs of the MMRV vaccine were non-inferior to that elicited by MMR+V vaccines for all antigens except mumps.

A 90-day study of sub-chronic oral toxicity of 20 nm positively charged zinc oxide nanoparticles in Sprague Dawley rats.

PURPOSE: The study reported here was conducted to determine the systemic oral toxicity and to find the no-observed-adverse-effect level of 20 nm positively charged zinc oxide (ZnO(SM20(+))) nanoparticles in Sprague Dawley rats for 90 days. METHODS: For the 90-day toxicity study, the high dose was set as 500 mg per kg of body weight (mg/kg) and the middle and low dose were set to 250 mg/kg and 125 mg/kg, respectively. The rats were held for a 14-day recovery period after the last administration, to observe for the persistence or reduction of any toxic effects. A distributional study was also carried out for the systemic distribution of ZnO(SM20(+)) NPs. RESULTS: No rats died during the test period. There were no significant clinical changes due to the test article during the experimental period in functional assessment, body weight, food and water consumption, ophthalmological testing, urine analysis, necropsy findings, or organ weights, but salivation was observed immediately after administration in both sexes. The total red blood cell count was increased, and hematocrit, albumin, mean cell volume, mean cell hemoglobin, and mean cell hemoglobin concentration were decreased significantly compared with control in both 500 mg/kg groups. Total protein and albumin levels were decreased significantly in both sexes in the 250 and 500 mg/kg groups. Histopathological studies revealed acinar cell apoptosis in the pancreas, inflammation and edema in stomach mucosa, and retinal atrophy of the eye in the 500 mg/kg group. CONCLUSION: There were significant parameter changes in terms of anemia in the hematological and blood chemical analyses in the 250 and 500 mg/kg groups. The significant toxic change was observed to be below 125 mg/kg, so the no-observed-adverse-effect level was not determined, but the lowest-observed-adverse-effect level was considered to be 125 mg/kg in both sexes and the target organs were found to be the pancreas, eye, and stomach.

Zinc oxide nanoparticles: a 90-day repeated-dose dermal toxicity study in rats.

Zinc oxide (ZnO) works as a long-lasting, broad-spectrum physical sunblock, and can prevent skin cancer, sunburn, and photoaging. Nanosized ZnO particles are used often in sunscreens due to consumer preference over larger sizes, which appear opaque when dermally applied. Although the US Food and Drug Administration approved the use of nanoparticles (NPs) in sunscreens in 1999, there are ongoing safety concerns. The aim of this study was to evaluate the subchronic toxicity of ZnO NPs after dermal application according to the Organization for Economic Cooperation and Development Test Guidelines 411 using Good Laboratory Practice. Sprague Dawley rats were randomly divided into eight (one control, one vehicle control, three experimental, and three recovery) groups. Different concentrations of ZnO NPs were dermally applied to the rats in the experimental groups for 90 days. Clinical observations as well as weight and food consumption were measured and recorded daily. Hematology and biochemistry parameters were determined. Gross pathologic and histopathologic examinations were performed on selected tissues from all animals. Analyses of tissue were undertaken to determine target organ tissue distribution. There was no increased mortality in the experimental group. Although there was dose-dependent irritation at the site of application, there were no abnormal findings related to ZnO NPs in other organs. Increased concentrations of ZnO in the liver, small intestine, large intestine, and feces were thought to result from oral ingestion of ZnO NPs via licking. Penetration of ZnO NPs through the skin seemed to be limited via the dermal route. This study demonstrates that there was no observed adverse effect of ZnO NPs up to 1,000 mg/kg body weight when they are applied dermally.

The role of a whole blood interferon-gamma assay for the detection of latent tuberculosis infection in Bacille Calmette-Guérin vaccinated children.

The tuberculin skin test (TST) has limitations in children who are under the Bacille Calmette-Guérin (BCG) effect. Our aim was to evaluate the QuantiFERON-TB Gold In-Tube (QFT-G IT) blood test for Mycobacterium tuberculosis infection in children and to compare results with those of the TST. QFT-G IT and TST data were collected from 227 children between 0 and 15 years of age, split into 4 risk groups. Forty-two children were close contacts, 29 were casual contacts, and 65 were controls. The QFT-G IT positivity rates were 19% (8/42), 6.9% (2/29), and 1.5% (1/65), with a significantly higher rate for the close contacts over the controls (P < 0.05). The high specificity of the QFT-G IT assay and the association of positive results with increasing risk of infection in our study suggest it has major benefits over the TST as a screening test for latent infection with M. tuberculosis in BCG-vaccinated children.

Low-dose methotrexate therapy for intravenous immunoglobulin-resistant Kawasaki disease.

PURPOSE: The aim of this study was to evaluate the efficacy of low-dose oral methotrexate (MTX) as a treatment for patients with Kawasaki disease (KD) which was resistant to intravenous immunoglobulin (IVIG). PATIENTS AND METHODS: The patients who had persistent or recrudescent fever after treatment with IVIG were subsequently treated with low-dose oral MTX [10mg/body surface area (BSA)] once weekly. RESULTS: Seventeen patients developed persistent or recrudescent fever after treatment of KD with IVIG and were consequently given MTX. The proportion of children with coronary artery lesions (CALs) was 76%. The median value of maximum body temperatures decreased significantly within 24 hours of MTX therapy (38.6 degrees C vs. 37.0 degrees C, p < 0.001). The median CRP (C-reactive protein) level was found to be significantly lower 1 week after administering the first dose of MTX (8.9mg/dL vs. 1.2mg/dL, p < 0.001). The median duration of fever before MTX treatment was shorter in CALs (-) group than in CALs (+) group (7 days vs. 10 days, p = 0.023). No adverse effects of MTX were observed. CONCLUSION: MTX treatment for IVIG-resistant KD resulted in quick resolution of fever and rapid improvement of inflammation markers without causing any adverse effects. MTX therapy should further be assessed in a multicenter, placebo-blinded trial to evaluate whether it also improves coronary artery outcome.

Analysis of clinical presentations of Bruton disease: a review of 20 years of accumulated data from pediatric patients at Severance Hospital.

PURPOSE: X-linked agammaglobulinemia (XLA) is a humoral immunodeficiency disease caused by a mutation in the Bruton tyrosine kinase (BTK) gene resulting in defective B cell differentiation. Because it is a relatively rare disorder, it is difficult for clinicians to have a comprehensive understanding of XLA due to a lack of exposure to the disease. Clinical presentations of patients with XLA were analyzed and discussed to improve care plans. MATERIALS AND METHODS: During a 20 year period, from January 1987 to June 2006, a total of 19 patients were diagnosed as XLA in the Department of Pediatrics at Severance Hospital, Seoul, Korea. A retrospective analysis of the clinical presentations of those patients was performed. RESULTS: The mean age of the XLA patients included in the study was 4.89 years, with a range of 6 months to 13 years. Twelve patients were diagnosed before age 5, while the other 7 patients were diagnosed after age 5. Recurrent infections observed in the patients included pneumonia, acute otitis media, septic arthritis, skin infection, sepsis, sinusitis, acute gastroenteritis, cervical lymphadenitis, epididymitis, meningitis, osteomyelitis, urinary tract infection and encephalitis. Frequency of admissions was variable from 0 to 12 times, depending on the time at which immunoglobulin therapy was started. Six cases had family histories positive for XLA. BTK gene mutations were found in 8 cases. CONCLUSION: The overall prognosis of XLA is good as long as patients are diagnosed and treated early with regular intra venous gamma globulin therapy before the sequelae of recurrent infections appear.

Immunogenicity and safety of a pentavalent human-bovine (WC3) reassortant rotavirus vaccine in healthy infants in Korea.

We evaluated the immunogenicity and safety of pentavalent human-bovine reassortant rotavirus vaccine in 178 Korean healthy infants. Seroresponse rate for serum antirotavirus IgA titers was 94.7% among 94 vaccine recipients, as compared with 13.5% among 52 placebo recipients. Seroresponse rates in serum neutralizing antibody to each human rotavirus serotype in the vaccine were significantly higher in the vaccine group than in the placebo group. This vaccine was generally well tolerated and immunogenic.