Although coronavirus disease 2019 (COVID-19) is an ongoing pandemic, the mean serial interval was measured differently across nations. Through the Korean national COVID-19 contact tracing system, we were able to investigate personal contacts in all symptomatic cases in Korea from January 20 to August 3, 2020. The mean serial interval was calculated by the duration between the symptom onset of the infector and infectee, and became shorter after the case definition changed to include not-imported cases in Korea on February 20, 2020. The mean serial interval before and after this fifth case definition was 6.12 and 3.93 days based on the infectors' symptom onset date, respectively, and 4.02 days in total with the median of 3 days. Older age and women lead to longer serial intervals.
  A population-based study would be useful to identify the association between chronic kidney disease (CKD) or acute kidney injury (AKI) and prognosis of coronavirus disease 2019 (COVID-19) patients.
 
  This retrospective study utilized the claim data from Korea. Patients who underwent COVID-19 testing and were confirmed to be positive were included and divided into the following three groups based on the presence of CKD or requirement of maintenance dialysis Non-CKD (participants without CKD), non-dialysis CKD (ND-CKD), and dialysis-dependent CKD (DD-CKD) patients. We collected data on the development of severe clinical outcomes and death during follow-up. Severe clinical outcomes were defined as the use of inotropics, conventional oxygen therapy, high-flow nasal cannula, mechanical ventilation, or extracorporeal membrane oxygenation and the development of AKI, cardiac arrest, myocardial infarction, or acute heart failure after the diagnosis of COVID-19. AKI was defined as the initiation of renal replacement rence in frequency of severe clinical outcomes or mortality rates between the Non-CKD and ND-CKD groups. In patients not requiring maintenance dialysis, AKI was associated with old age, male sex, and high Charlson's comorbidity index score but not with the presence of CKD. HRs for patients with AKI were 11.26 (95% CI, 7.26-17.45; 
  < 0.001) compared to those for patients without AKI in the multivariate analysis.  https://www.selleckchem.com/products/ulonivirine.html  AKI was associated with severe clinical outcomes and patient survival, rather than underlying CKD.
 
  CKD requiring dialysis is associated with severe clinical outcomes and mortality in patients with COVID-19; however, the development of AKI is more strongly associated with severe clinical outcomes and mortality.
 CKD requiring dialysis is associated with severe clinical outcomes and mortality in patients with COVID-19; however, the development of AKI is more strongly associated with severe clinical outcomes and mortality.From January to September 2020, we conducted contact-tracing for confirmed coronavirus disease 2019 (COVID-19) patients who visited our outpatient clinic to evaluate the risk of COVID-19 transmission from infected patients to healthcare workers (HCWs). COVID-19 was diagnosed in 8 outpatients. Per the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) polymerase chain reaction test results, none of the 317 HCWs who came in contact had a confirmed COVID-19 diagnosis (0.00%; 95% confidence interval, 0.00%-0.01%). This low rate of transmission from infected outpatients to HCWs suggests that standard precaution such as using surgical mask and hand hygiene protects HCWs from SARS-CoV-2 in a low-risk, outpatient clinic setting.
  For the first time in Korea, we aimed to study the efficacy and safety of cannabidiol (CBD), which is emerging as a new alternative in treating epileptic encephalopathies.
 
  This study was conducted retrospectively with patients between the ages of 2-18 years diagnosed with Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) were enrolled from March to October 2019, who visited outpatient unit at 3 and 6 months to evaluate medication efficacy and safety based on caregiver reporting. Additional evaluations, such as electroencephalogram and blood tests, were conducted at each period also. CBD was administered orally at a starting dose of 5 mg/kg/day, and was maintained at 10 mg/kg/day.
 
  We analyzed 34 patients in the LGS group and 10 patients in the DS group between the ages of 1.2-15.8 years. In the 3-month evaluation, the overall reduction of seizure frequency in the LGS group was 52.9% (>50% reduction in 32.3% of the cases), and 29.4% in the 6-month evaluation (more than 50% reduction in 20.6%). In DS group, the reduction of seizure frequency by more than 50% was 30% and 20% in the 3-month and 6-month evaluation, respectively. Good outcomes were defined as the reduction of seizure frequency by more than 50% and similar results were observed in both LGS and DS groups. Adverse events were reported in 36.3% of total patients of which most common adverse events were gastrointestinal problems. However, no life-threatening adverse event was reported in both LGS and DS during the observation period.
 
  In this first Korean study, CBD was safe and tolerable for use and could be expected to potentially reduce the seizure frequency in pediatric patients with LGS or DS.
 In this first Korean study, CBD was safe and tolerable for use and could be expected to potentially reduce the seizure frequency in pediatric patients with LGS or DS.
  This study aimed to investigate the impact of exposure to adverse childhood experiences (ACEs) and stress among the community-based urban pediatric population in Korea.
 
  In 2017, the analysis was conducted on 3,937 children and adolescents in an urban area in Korea based on the impact of actual traumatic experience, addiction, and mental health. The respondents were excluded if they were missing data on the survey, resulting in a final sample size of 3,556. The collected data were analyzed by applying cross-sectional and correlation analyses.
 
  Among the respondents in the study group (mean age = 13.77), 43.1% were boys (n = 1,532) and 56.9% were girls (n = 2,024). Overall, 23.5% (n = 835) reported at least one ACE and 1.8% (n = 63) reported experiencing four or more ACEs. Emotional abuse (13.2%) was the most commonly reported ACE, followed by abandonment (7.7%) and physical abuse (7.5%). Self-reported measures of stress were associated with the ACE scores.
 
  This is the first study of self-reported ACEs from a community-based pediatric population in Korea.