Methods
A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines (22), a comprehensive search was performed in PubMed, Scopus, MEDLINE, and EMBASE Databases for research publications on COVID-19 published between December 2019 and October 2021 using the terms COVID-19, Pediatrics, children, adolescents, SARS-CoV-2, Epidemiology, and Vaccine. Phrases used for the Medical Subject Heading [MeSH] search included: (((“COVID-19” [MeSH]) and “Vaccine” [MeSH]) and “Children” [MeSH]) and “adolescents” [MeSH]) and “Pfizer” [MeSH]. We focused on original research, case reports, case series, and vaccination side-effect by authoritative health institutions. All records were retrieved, including original articles, letters to the editor, editorials, and case reports, in English, and records with English translation were downloaded and reviewed. Given the current scarcity of evidence, preprints, in-press papers, and accepted-for-publication research were also considered.