Adolescence is a crucial period characterized by profound physical, psychological, and social changes that significantly shape the transition into adulthood. Beyond individual traits, each generation encounters unique contextual challenges, adding layers of complexity to the journey through adolescence. The COVID-19 pandemic may have had a deleterious impact on the lives of children and adolescents, and its long-term effects warrant special consideration. This thesis research, initiated in 2021 alongside the SEROCoV-Kids study—one of Switzerland's biggest paediatric cohorts—aims to examine and monitor the direct and indirect effects of the pandemic and related societal changes on adolescent lives.