Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to many countries, resulting in a global public health threat. The World Health Organization characterized COVID-19 as a pandemic on March 11, 2020, and as of April 20, 2 314 621 confirmed cases and 157 847 fatal cases have been reported.¹

Coronavirus disease-2019 (COVID-19), which started in Wuhan, China, in December 2019 and declared a worldwide pandemic on March 11, 2020, is a novel infectious disease that causes respiratory illness and death. Pediatric COVID-19 accounts for a small percentage of patients and is often milder than that in adults; however, it can progress to severe disease in some cases. Even neonates can suffer from COVID-19, and children may spread the disease in the community. This review summarizes what is currently known about COVID-19 in children and adolescents.

In Korea, the prevalence of anemia and iron deficiency anemia (IDA) among older infants and young children remains high. To detect IDA early and to reduce its adverse impact, we assessed the characteristics of infants and young children who had IDA or were at risk of developing IDA, or who exhibited characteristics associated with severe anemia. Among the 1,782 IDA-affected children aged 6 months to 18 years who visited the hospital, we retrospectively analyzed the medical records and laboratory data of 1,330 IDA-affected children aged 6-23 months who were diagnosed between 1996 and 2013. We excluded patients with a C-reactive protein level ≥5 mg/dL. IDA was predominant in boys (2.14:1) during infancy and early childhood. The peak IDA incidence was noted among infants aged 9-12 months. Only 7% patients exhibited symptoms of IDA, while 23.6% patients with severe IDA demonstrated classic symptoms/signs of IDA. Low birth weight (LBW) infants with IDA demonstrated low adherence to iron supplementation. In a multivariate analysis, prolonged breastfeeding without iron fortification (odds ratio [OR] 5.70), and a LBW (OR 6.49) were identified as risk factors of severe anemia. LBW infants need more attention in order to increase their adherence to iron supplementation. For the early detection of IDA, nutritional status of all infants, and iron batteries of high-risk infants (LBW infants, infants with prolonged breastfeeding, picky eaters, and/or infants with the presence of IDA symptoms) should be evaluated at their health screening visits.

Background: In recent decades, the amount of data about allergic rhinitis (AR) in Korean National Health Insurance Service has increased. Objective: To investigate the prevalence and quality of sensitized allergens of AR in Korean children and adolescents. Methods: This study obtained the results of the Korean International Study of Asthma and Allergies in Childhood questionnaires and the skin-prick test (SPT) results of 14,356 students who participated in a health screening from 2010 to 2014. AR was defined as one with current symptoms of AR with at least one or more positive results of an SPT with inhalant allergens. Results: The prevalence of AR in children was 20.8%. Positive rates of the allergen group were 87.3% for house-dust mites, 37.0% for pollen, 12.4% for mold, and 8.4% for pets. The common allergens in descending order were Dermatophagoides pteronyssinus, Dermatophagoides farinae, Betula, Humulus, Alnus, and Alternaria. As the children became older, pollen-sensitization rates tended to increase (p value for trends, <0.001). In metropolitan and middle inland areas, weed pollen was the most common pollen. The rates of tree-pollen sensitization were the highest at the seaside and in the southern inland. The most common comorbid allergic diseases associated with AR were pollen allergy and allergic conjunctivitis at 37.0% and 34.5%, respectively. Conclusions: This was the first study conducted in Korea to investigate the prevalence of AR in the general population by using both questionnaires and SPTs. The allergens used for the SPTs were chosen based on the common allergens in this study, and this current pollen data will contribute to establish the cause of increasing AR prevalence in Korea.

Background: The aims of this study were to investigate the prevalence of allergic rhinitis (AR) and the accuracy of the International Study of Asthma and Allergies in Childhood (ISAAC) questions for diagnosis of AR, in Korean children. Methods: Students that participated in an allergic disease prevalence survey in 2010–2017 were evaluated (n = 18,425) using questionnaires and a skin prick test (SPT). Age−stratified (5−7, 8−10, 11−13, 14−16 years) prevalence of four rhinitis questions, accuracy of the questions for AR, and proportion of comorbidities in the AR and non-AR (NAR) groups were evaluated. Results: The proportion of students responding to the questionnaire that ever had symptoms of AR since birth, that is, the prevalence of “symptom, ever” was 47.6%. Based on the questionnaire and SPT, overall prevalence of AR and NAR were 21% and 26.5%, respectively. The sensitivity, specificity, and accuracy of “symptom, ever” were 57.5%, 58.4%, and 58.1%, respectively, and those of “diagnosis, ever”, who had ever been diagnosed with AR, were 39.8%, 76.9%, and 63.4%, respectively. Questionnaire−based asthma, atopic dermatitis, and food allergy were significantly associated with the AR group compared to the NAR group. Conclusions: Since the AR accuracy of the questionnaire is about 60%, it should be considered that the questionnaire based survey overestimates the true prevalence of AR in Korean children.