Research is being conducted on the effectiveness of covid-19 vaccines, including BNT162b2 and CoronaVac, in children and adolescents against SARS-CoV-2 infection, particularly during the Omicron BA.2 wave. Studies are examining vaccine effectiveness in various locations, including Hong Kong, Brazil, and China. The research encompasses different aspects, such as immune responses, transmission risks, and efficacy in preventing asymptomatic and symptomatic infection.