en عفونی Infectious Diseases Original Article Original Article <strong>Background</strong>: COVID-19 is a highly infectious and contagious disease. Since the outbreak of COVID-19, most studies on children have focused on the incidence and prognosis of the disease, and few studies have investigated the epidemiological characteristics of the disease.&nbsp;<br> Objectives: This study aimed to investigate some epidemiological aspects of the disease in children with COVID-19.&nbsp;<br> <strong>Methods</strong>: We examined children with COVID-19 (under 18 years) hospitalized in the North East of Iran from the beginning of the outbreak until the end of September 2020. Study information was collected from patients&rsquo; medical records and interviews with their parents. We recorded demographic data; history of diseases and taking medicine in children; educational, occupational, and smoking status of parents; patients&rsquo; residence conditions; and any report of COVID-19 in patients&rsquo; families and relatives.<br> <strong>Results</strong>: Of 107 children studied, 57% were male, and 52.3% had no underlying disease. The mean age of patients was 67 months. The Mean&plusmn;SD weight of the children was 20.36&plusmn;13.75 kg, and their Mean&plusmn;SD length of hospital stay was 9&plusmn;8 days. Multisystem inflammatory syndrome in children (MIS-C) was observed in 34.6% of patients, and its relationship with death was highly significant (P=0.001). The length of hospital stay was influenced by the history of medication consumption (P=0.013) and underlying disease (P=0.001), and its increase was associated with an increased risk of MIS-C (P=0.032) and death (P=0.047).<br> <strong>Conclusions</strong>: Male sex, length of hospital stay, and MIS-C were identified as risk factors associated with worsening the outcome of COVID-19 disease in children. Children, COVID-19, Epidemiology, Multisystem iMIS-C, SARS-CoV-2 445 454 http://jpr.mazums.ac.ir/browse.php?a_code=A-10-919-2&slc_lang=en&sid=1 Maryam Naseri maryamnaseri63@yahoo.com 10031947532846007947 10031947532846007947 No Department of Pediatrics, Mashhad University of Medical Sciences, Mashhad, Iran. Gholamreza Khademi khademigh@mums.ac.ir 10031947532846007948 10031947532846007948 No Neonatal Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Majid Khadem Rezaeian KhademRM@mums.ac.ir 10031947532846007949 10031947532846007949 No Clinical Research Development Unit of Akbar Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Shahabaldin Sorouri Shahab_S59@yahoo.com 10031947532846007950 10031947532846007950 No Internal Department, Mashhad University of Medical Sciences, Mashhad, Iran. Majid Sezavar sezavardm@mums.ac.ir 10031947532846007951 10031947532846007951 Yes Department of Pediatrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.