Childhood Infection and Immunity Longitudinal Cohort

This prospective observational study will enroll approximately 1,200 children from birth through 7 years of age in Zhejiang Province, China. Participants will include general healthy children from the community, children with a history of serious or recurrent infections, and children with confirmed or highly suspected asthma. No treatment will be assigned by the researchers. Health information will be collected through questionnaires, vaccination and medical records, regular follow-up, and active surveillance of respiratory infections. Blood, stool, and nasopharyngeal swab samples will be collected at enrollment and annual visits. Additional blood and respiratory samples will be collected during selected respiratory infection events. Laboratory assessments may include antibody, pathogen, microbiome, and single-cell analyses. The study aims to characterize biomarkers of anti-infective immunity in children and assess their risk of infection. Xiamen University, Zhejiang Provincial Center for Disease Control and Prevention, and Xiang An Biomedicine Laboratory are the co-sponsors of this study. Hanqing He (Zhejiang Provincial CDC) and Tianying Zhang (Xiamen University) serve as the co-principal investigators.