Background: Primary cutaneous CD30+ lymphoproliferative disorders (pcCD30-LPDs) are a diseases with various clinical and prognostic characteristics. Objective: Increasing our knowledge of the clinical characteristics of pcCD30-LPDs and identifying potential prognostic variables in an Asian population. Methods: Clinicopathological features and survival data of pcCD30-LPD cases obtained from 22 hospitals in South Korea were examined. Results: A total of 413 cases of pcCD30-LPDs (lymphomatoid papulosis [LYP], n=237; primary cutaneous anaplastic large cell lymphoma [C-ALCL], n=176) were included. Ninety percent of LYP patients and roughly 50% of C-ALCL patients presented with multiple skin lesions. Both LYP and C-ALCL affected the lower limbs most frequently. Multiplicity and advanced T stage of LYP lesions were associated with a chronic course longer than 6 months. Clinical morphology with patch lesions and elevated serum lactate dehydrogenase were significantly associated with LPDs during follow-up in LYP patients. Extracutaneous involvement of C-ALCL occurred in 13.2% of patients. Lesions larger than 5 cm and increased serum lactate dehydrogenase were associated with a poor prognosis in C-ALCL. The survival of patients with C-ALCL was unaffected by the anatomical locations of skin lesions or other pathological factors. Conclusion The multiplicity or size of skin lesions was associated with a chronic course of LYP and survival among patients with C-ALCL.

Background: The relationship between early life factors and childhood pulmonary function and structure in preterm infants remains unclear.Purpose: This study investigated the impact of bronchopulmonary dysplasia (BPD) and perinatal factors on childhood pulmonary function and structure. Methods: This longitudinal cohort study included preterm participants aged ≥5 years born between 2005 and 2015. The children were grouped by BPD severity according to National Institutes of Health criteria. Pulmonary function tests (PFTs) were performed using spirometry. Chest computed tomography (CT) scans were obtained and scored for hyperaeration or parenchymal lesions. PFT results and chest CT scores were analyzed with perinatal factors. Results: A total 150 children (66 females) aged 7.7 years (6.4–9.9 years) were categorized into non/mild BPD (n=68), moderate BPD (n=39), and severe BPD (n=43) groups. The median z score for forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and forced midexpiratory flow (FEF25%–75%) were significantly lower in the severe versus non/mild BPD group (-1.24 vs. -0.18, -0.22 vs. 0.41, -1.80 vs. -1.12, and -1.88 vs. -1.00, respectively; all P<0.05). The median z scores of FEV1, FEV1/ FVC, and FEF25%–75% among asymptomatic patients were also significantly lower in the severe versus non/mild BPD group (-0.82 vs. 0.09, -1.68 vs. -0.87, -1.59 vs. -0.61, respectively; all P<0.05). The severe BPD group had a higher median (range) CT score than the non/mild BPD group (6 [0–12] vs. 1 [0–10], P<0.001). Prenatal oligohydramnios was strongly associated with both low pulmonary function (FEV1/FVCConclusion School-aged children with severe BPD showed airflow limitations and structural abnormalities despite no subjective respiratory symptoms. These results suggest that patients with a history of prenatal oligohydramnios or prolonged mechanical ventilation require extended follow-up.

Background: The relationship between early life factors and childhood pulmonary function and structure in preterm infants remains unclear.Purpose: This study investigated the impact of bronchopulmonary dysplasia (BPD) and perinatal factors on childhood pulmonary function and structure. Methods: This longitudinal cohort study included preterm participants aged ≥5 years born between 2005 and 2015. The children were grouped by BPD severity according to National Institutes of Health criteria. Pulmonary function tests (PFTs) were performed using spirometry. Chest computed tomography (CT) scans were obtained and scored for hyperaeration or parenchymal lesions. PFT results and chest CT scores were analyzed with perinatal factors. Results: A total 150 children (66 females) aged 7.7 years (6.4–9.9 years) were categorized into non/mild BPD (n=68), moderate BPD (n=39), and severe BPD (n=43) groups. The median z score for forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and forced midexpiratory flow (FEF25%–75%) were significantly lower in the severe versus non/mild BPD group (-1.24 vs. -0.18, -0.22 vs. 0.41, -1.80 vs. -1.12, and -1.88 vs. -1.00, respectively; all P<0.05). The median z scores of FEV1, FEV1/ FVC, and FEF25%–75% among asymptomatic patients were also significantly lower in the severe versus non/mild BPD group (-0.82 vs. 0.09, -1.68 vs. -0.87, -1.59 vs. -0.61, respectively; all P<0.05). The severe BPD group had a higher median (range) CT score than the non/mild BPD group (6 [0–12] vs. 1 [0–10], P<0.001). Prenatal oligohydramnios was strongly associated with both low pulmonary function (FEV1/FVCConclusion School-aged children with severe BPD showed airflow limitations and structural abnormalities despite no subjective respiratory symptoms. These results suggest that patients with a history of prenatal oligohydramnios or prolonged mechanical ventilation require extended follow-up.

Background: The relationship between early life factors and childhood pulmonary function and structure in preterm infants remains unclear.Purpose: This study investigated the impact of bronchopulmonary dysplasia (BPD) and perinatal factors on childhood pulmonary function and structure. Methods: This longitudinal cohort study included preterm participants aged ≥5 years born between 2005 and 2015. The children were grouped by BPD severity according to National Institutes of Health criteria. Pulmonary function tests (PFTs) were performed using spirometry. Chest computed tomography (CT) scans were obtained and scored for hyperaeration or parenchymal lesions. PFT results and chest CT scores were analyzed with perinatal factors. Results: A total 150 children (66 females) aged 7.7 years (6.4–9.9 years) were categorized into non/mild BPD (n=68), moderate BPD (n=39), and severe BPD (n=43) groups. The median z score for forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and forced midexpiratory flow (FEF25%–75%) were significantly lower in the severe versus non/mild BPD group (-1.24 vs. -0.18, -0.22 vs. 0.41, -1.80 vs. -1.12, and -1.88 vs. -1.00, respectively; all P<0.05). The median z scores of FEV1, FEV1/ FVC, and FEF25%–75% among asymptomatic patients were also significantly lower in the severe versus non/mild BPD group (-0.82 vs. 0.09, -1.68 vs. -0.87, -1.59 vs. -0.61, respectively; all P<0.05). The severe BPD group had a higher median (range) CT score than the non/mild BPD group (6 [0–12] vs. 1 [0–10], P<0.001). Prenatal oligohydramnios was strongly associated with both low pulmonary function (FEV1/FVCConclusion School-aged children with severe BPD showed airflow limitations and structural abnormalities despite no subjective respiratory symptoms. These results suggest that patients with a history of prenatal oligohydramnios or prolonged mechanical ventilation require extended follow-up.

Background: The relationship between early life factors and childhood pulmonary function and structure in preterm infants remains unclear.Purpose: This study investigated the impact of bronchopulmonary dysplasia (BPD) and perinatal factors on childhood pulmonary function and structure. Methods: This longitudinal cohort study included preterm participants aged ≥5 years born between 2005 and 2015. The children were grouped by BPD severity according to National Institutes of Health criteria. Pulmonary function tests (PFTs) were performed using spirometry. Chest computed tomography (CT) scans were obtained and scored for hyperaeration or parenchymal lesions. PFT results and chest CT scores were analyzed with perinatal factors. Results: A total 150 children (66 females) aged 7.7 years (6.4–9.9 years) were categorized into non/mild BPD (n=68), moderate BPD (n=39), and severe BPD (n=43) groups. The median z score for forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and forced midexpiratory flow (FEF25%–75%) were significantly lower in the severe versus non/mild BPD group (-1.24 vs. -0.18, -0.22 vs. 0.41, -1.80 vs. -1.12, and -1.88 vs. -1.00, respectively; all P<0.05). The median z scores of FEV1, FEV1/ FVC, and FEF25%–75% among asymptomatic patients were also significantly lower in the severe versus non/mild BPD group (-0.82 vs. 0.09, -1.68 vs. -0.87, -1.59 vs. -0.61, respectively; all P<0.05). The severe BPD group had a higher median (range) CT score than the non/mild BPD group (6 [0–12] vs. 1 [0–10], P<0.001). Prenatal oligohydramnios was strongly associated with both low pulmonary function (FEV1/FVCConclusion School-aged children with severe BPD showed airflow limitations and structural abnormalities despite no subjective respiratory symptoms. These results suggest that patients with a history of prenatal oligohydramnios or prolonged mechanical ventilation require extended follow-up.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: This study aimed to investigate the epidemiological characteristics and outcomes of myocarditis/pericarditis after BNT162b2 vaccination in Korean adolescents. Methods: This was a retrospective cohort analysis of adolescents aged 12–19 years old diagnosed with myocarditis/pericarditis within 42 days of BNT162b2 mRNA vaccination. All reported cases were investigated by city or government epidemiologists and the diagnostic certainty and causality was determined by the Korea Disease Control and Prevention Agency’s Adverse Event Following Immunization Expert Advisory Committee according to the modified version of Brighton Collaboration Myocarditis/Pericarditis Working group’s case definitions. Results: A total 3,709,063 adolescents aged 12–19 received 8,135,240 doses of the BNT162b2 vaccine in South Korea, and 184 cases met the Brighton criteria for the case definition of myocarditis and pericarditis with diagnostic certainty of possible and above. The median age was 17 years old (interquartile range [IQR], 15–18) and boys accounted for 81.5% (n = 150/184) of the cases. The overall incidence was 2.25 (95% confidence interval [CI], 1.94–2.60) cases per 100,000 doses and severe cases was 0.25 (95% CI, 0.15–3.80) cases per 100,000 doses.The highest incidence rate was observed in boys after the second dose, with 5.01 (95% CI, 4.12–6.17) cases per 100,000 doses. A total 89.1% (164/184) were classified as mild, and no deaths were reported. Conclusion The highest incidence of myocarditis/pericarditis after BNT162b2 immunization was observed in male adolescents after the second dose, with majority of the cases presenting with a mild clinical course and favorable outcome.

Background: Since the emergence of hypervirulent strains of Clostridioides difficile, the incidence of C. difficile infections (CDI) has increased significantly. Methods: To assess the incidence of CDI in Korea, we conducted a prospective multicentre observational study from October 2020 to October 2021. Additionally, we calculated the incidence of CDI from mass data obtained from the Health Insurance Review and Assessment Service (HIRA) from 2008 to 2020. Results: In the prospective study with active surveillance, 30,212 patients had diarrhoea and 907 patients were diagnosed with CDI over 1,288,571 patient-days and 193,264 admissions in 18 participating hospitals during 3 months of study period; the CDI per 10,000 patientdays was 7.04 and the CDI per 1,000 admission was 4.69. The incidence of CDI was higher in general hospitals than in tertiary hospitals: 6.38 per 10,000 patient-days (range: 3.25–12.05) and 4.18 per 1,000 admissions (range: 1.92–8.59) in 11 tertiary hospitals, vs. 9.45 per 10,000 patient-days (range: 5.68–13.90) and 6.73 per 1,000 admissions (range: 3.18–15.85) in seven general hospitals. With regard to HIRA data, the incidence of CDI in all hospitals has been increasing over the 13-year-period: from 0.3 to 1.8 per 10,000 patient-days, 0.3 to 1.6 per 1,000 admissions, and 6.9 to 56.9 per 100,000 population, respectively. Conclusion The incidence of CDI in Korea has been gradually increasing, and its recent value is as high as that in the United State and Europe. CDI is underestimated, particularly in general hospitals in Korea.