RecruitingEarly Phase 1Biological interventionMOdification Of THe Early-Life Respiratory Microbiome Through Vaginal SEEDingThis is a single-center, parallel-arm, blind, sham-controlled, feasibility randomized controlled trial (RCT) to be conducted in healthy cesarean-born children. Eligible children will be randomized 1:1 to have their nose swabbed with either maternal vaginal secretions or a sterile swab (intervention vs. control group, respectively). The main hypothesis is that conducting an RCT assessing the utility of vaginal seeding in modifying the early-life upper respiratory tract (URT) microbiome of children born by cesarean section (C-section) is feasible and that the intervention is safe.