In parallel, further studies should investigate the kinetics of humoral immune response to SARS-CoV-2 infection in children, as well as the cellular response, in order to identify new potential markers of previous SARS-CoV-2 infection such as SARS-CoV-2-specific CD4+ T cells or SARS-CoV-2 receptor-binding domain (RBD)-specific memory B-cells, which have been shown to remain stable even 12 months after the infection in adult patients [32]. Here, CD4 is linked to infection.