Effectiveness of COVID-19 vaccines among children and adolescents against SARS-CoV-2 variants: a meta-analysis

This systematic review and meta-analysis aimed to evaluate the effectiveness of COVID-19 vaccines among children and adolescents against SARS-CoV-2 variants. We searched PubMed, Embase, Web of Science, the Cochrane Library, and ClinicalTrials.gov for studies published on or before June 20, 2023. Studies evaluating the effectiveness of COVID-19 vaccines in children and adolescents (≤ 18 years of age) were included. Data extraction, quality assessment, and analysis were conducted following PRISMA guidelines. Ten studies were included, comprising five cohort studies (527,778 participants) and four case-control studies (1,477,422 participants). The overall vaccine effectiveness (VE) against SARS-CoV-2 variants was 68% (95% CI = 60–74%). In terms of age, the VE was higher in adolescents aged 12–18 years [69%(95% CI = 61–75%)] than in children aged 5–11 years [44%(95% CI = 1–68%)]. “Fully vaccinated” may offer greater protection than “partially vaccinated,” with a VE of 71% (95%CI = 59–79%) and 66% (95%CI = 51–76%), respectively.