Background & aimsConcomitantly to the coronavirus disease 2019 (COVID-19), in the child population there was already another pandemic wave in progress: childhood obesity. Numerous studies in adults have been carried out and describe obesity as an independent risk and prognostic factor for the severity of COVID-19. This study aims to systematically review the literature on the relation between weight excess and the severity of COVID-19 in children and adolescents.MethodsThis systematic review was developed following the PRISMA standards (Preferred Reporting Items for Systematic Review and Meta-Analysis). The literature search was performed in September 2020, in the following databases: MEDLINE (via PubMed), Embase, Scopus, The Cochrane Library (Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials (CENTRAL)), Web of Science, BVS/LILACS and SciELO. Registration on the PROSPERO platform (International Prospective Registry of Systematic Reviews) can be found under the registration number: CRD42021230686.ResultsOf the 667 selected articles, 11 were included according to all agreed criteria, most of them being unicentric and American. In assessing the risk of bias and quality, following the criteria of the Newcastle–Ottawa Scale, eight studies achieved scores higher than 7. Only 5 studies sought to assess obesity and its relation with worse outcomes (such as need for pediatric intensive care unit (PICU), mechanical ventilation (MV), tracheostomy, hospital readmission and mortality), and out of these, only one article demonstrated this comorbidity as a prognostic factor for worse evolution of the COVID picture.ConclusionsFew studies in the literature seek to assess excess weight and its relation with worse outcomes of COVID-19 in children and adolescents. Taking into account that there is already scientific evidence on this subject in adult patients, it is necessary to carry out more research in the pediatric age group.