Safety, Immunogenicity, and Efficacy of COVID-19 Vaccine in Children and Adolescents: A Systematic Review

Abstract

Aim To identify the safety, immunogenicity, and protective efficacy of COVID-19 vaccine in children and adolescents. Methods We conducted a systematic review. Databases including PubMed, Web of Science, WHO COVID-19 database, and CNKI were searched on 23 July 2021. International Clinical Trials Registry Platform (ICTRP) was also searched to collect ongoing trials. We included published researches or ongoing clinical trials related to the safety, immunogenicity, and efficacy of COVID-19 vaccine in children or adolescents (aged [≤]18 years). Meta-analysis was performed if the consistency of the included studies was high. If not, descriptive analyses were performed. Results Eight published studies with 2851 children or adolescents and 28 ongoing clinical trials were included. Among eight published studies, two (25.0%) were RCTs, two (25.0%) case series, and four (50.0%) case reports. The results showed selected COVID-19 vaccines had a good safety profile in children and adolescents. Injection site pain, fatigue, headache, and chest pain were the most common adverse events. Some studies reported a few cases of myocarditis and pericarditis. Two RCTs showed that the immune response to BNT162b2 in adolescents aged 12-15 years was non-inferior to that in young people aged 16-25 years, while a stronger immune response was detected with 3g CoronaVac injection. Only one single RCT showed the efficacy of BNT162b2 was 100% (95% CI: 75.3 to 100). Of the 28 ongoing clinical trials, twenty-three are interventional studies. Fifteen countries are conducting interventional clinical trials of COVID-19 vaccines in children and adolescents. Among them, China (10, 43.5%) and United Stated (9, 39.1%) were the top two countries with the most trials. BNT162b2 was the most common vaccine, which is under testing. Conclusion Some of the COVID-19 vaccines have potential protective effects in children and adolescents, but awareness is needed to monitor possible adverse effects after injection. Clinical trials of the COVID-19 vaccine in children and adolescents with long follow-up, large sample size, and different vaccines are still urgently needed.