LAUSR

We read with great interest the study by Mantovani et al. (Vol. 89, issue 4). The authors aimed to assess the overall prevalence of clinical signs, symptoms and radiological findings in children and/or adolescents with COVID-19. We want to congratulate the authors for establishing a timely and informative systematic review of COVID-19 in children. Certainly, the findings of Mantovani et al. hold significance for pediatricians. However, we would like to draw their attention to the following issues. First, according to the exclusion criteria, the authors stated that ‘papers in non-English language were excluded’. However, the references 21, 27 and 28 included in this study were all published in Chinese. Furthermore, the authors failed to exclude studies suspected of including duplicate reporting. Some children or adolescents may have been included in multiple publications, as admission dates overlap for reports from the same hospital. Several studies were published by the same hospital with the periods of recruitment overlapped. Including duplicates may introduce bias into a systematic review and may affect understanding the disease and its epidemiology. Studies suspected of including duplicate reporting can be identified based on hospital location, participant admission date, maternal and neonatal characteristics, and outcomes. Thus, we suggest that the authors extract the setting/ hospital and recruitment periods to reduce the overlapping risk. Jianghui Cai, Yonghong Lin and Meng-jun Wu1 Chengdu Women’s and Children’s Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China. ✉email: [email protected] REFERENCES