SARS-CoV-2 infections among children and adolescents cause less severe illness and fewer deaths compared to adults. While a less severe course of infection is a positive outcome, there are concerns that mild symptoms may have led to less testing, resulting in fewer identified cases of COVID-19 in children. If children with mild or no symptoms transmit the disease, they may act as drivers of transmission within their communities. Understanding symptoms, infectivity and patterns of SARS-CoV-2 transmission in children and adolescents is essential for developing, adapting and improving control measures for COVID-19 across all ages. This is a summary of the current knowledge around SARS-CoV-2 infection acquisition and transmission and COVID-19 disease symptoms in children and adolescents. It aims to inform decisions, based on local contexts, on how to best keep schools, kindergarten and day-care facilities open and what advice to apply to intergenerational mixing.