evidence: SARS-CoV-2-targeting mRNA vaccines have become available for individuals six months of age and older5,6,7,8,9,10,11. These vaccines have provided substantial protection against hospitalizations and severe disease in children ages 5–17 years5,7,10,12. Moreover, detailed humoral profiling of children and adolescents reveals that mRNA COVID-19 vaccines elicit robust, highly functional humoral immune responses in children in a dose-dependent manner13, with strong cross-reactivity against variants of concerns (VOC)13,14. In children under 5 years of age, mRNA vaccination results in neutralizing immunoglobulin titers comparable to vaccinated adults and vaccination protects against symptomatic infection11. However, detailed humoral profiling in this age group has not yet been investigated. As an individual’s humoral immune response evolves with age15, age-related differences in mRNA vaccine responses must be fully characterized to fully understand the impact of mRNA vaccination in infants and toddlers. [...] Bartsch, Y. C. et al. SARS-CoV-2 mRNA vaccination elicits robust antibody responses in children. Sci. Transl. Med., eabn9237 (2022). [...] Jalkanen, P. et al. COVID-19 mRNA vaccine induced antibody responses against three SARS-CoV-2 variants. Nat. Commun.12, 3991 (2021).