Childhood Infection and Immunity Longitudinal Cohort

ClinicalTrials.gov ID

NCT07815925

Lead Sponsor

Zhejiang Provincial Center for Disease Control and PreventionOTHER_GOV

Overall Status

Not yet recruiting

Study Type

Observational

Enrollment

1,200Estimated

Last Update Posted

Sep 11, 2026Actual

Start Date

Sep 10, 2026Estimated

Primary Completion Date

Dec 31, 2036Estimated

Completion Date

Dec 31, 2036Estimated

Official Title

Childhood Infection and Immunity Longitudinal Cohort (KIDTRACE)

Brief Summary

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.

Detailed Description

This prospective observational cohort study combines scheduled longitudinal assessments, active surveillance of respiratory infections, healthcare data linkage, and biospecimen-based laboratory analyses to characterize biomarkers of anti-infective immunity in children and assess their risk of infection.

Questionnaire data and biological samples will be collected at baseline and annual visits. Respiratory infection events will be monitored through regular contact with participants' families, voluntary symptom reporting, sentinel hospital surveillance, and available healthcare records. Remote follow-up will generally occur every 8 to 12 weeks and may increase to every 4 weeks during periods of increased respiratory pathogen activity.

Eligible respiratory infection events will trigger acute-phase sampling, preferably within 3 days after illness onset or at the initial clinical visit, and recovery-phase sampling at 21 ± 4 days after onset. All eligible respiratory infection-related hospitalizations will trigger sampling. Outpatient or emergency department events may trigger sampling no more than twice per participant per year, with an interval of at least 6 weeks between events.

Laboratory assessments may include vaccine- and pathogen-specific antibodies, respiratory pathogen detection, cytokines, gut microbiome analysis, genomic analysis, and selected single-cell analyses.

• Immunity
• Respiratory Infection
• Asthma

Ages Eligible for Study

Child (0-17)

Sexes Eligible for Study

All

Accepts Healthy Volunteers

Yes

Eligibility Criteria

Inclusion Criteria:

• Children from birth through 7 years of age (younger than 8 years at enrollment).
• The participant's parent or legal guardian is able to understand the study, voluntarily agrees to participation, and provides written informed consent.
• The participant resides in the study area and is expected to be available for long-term follow-up.
• For the General Community Cohort: no known serious underlying disease before enrollment.
• For the Infection Observation Cohort: either a history of hospitalization for an infectious disease before 3 years of age, with documented information on the pathogen, infection site, or clinical diagnosis; or at least three healthcare visits for respiratory infections during the 12 months before enrollment.
• For the Childhood Asthma Cohort: physician-confirmed asthma or highly suspected asthma according to the protocol-defined age-specific criteria. Children younger than 1 year will not be included in this cohort.

Exclusion Criteria:

• An acute illness within 14 days before enrollment, including respiratory, gastrointestinal, dermatologic, or urinary symptoms or conditions specified in the protocol.
• Known primary immunodeficiency, malignant tumor, serious congenital disorder, or another condition that may substantially alter immune status.
• Long-term use of immunosuppressive or other immunomodulatory medications, defined as continuous or intermittent use for a cumulative duration of at least 3 months.
• A diagnosed coagulation abnormality or bleeding disorder, including coagulation factor deficiency, other coagulation disorders, or platelet abnormalities.
• Any other condition that, in the investigator's judgment, makes the child unsuitable for participation.

Observational Model

Cohort

Time Perspective

Prospective

Lead Sponsor

Zhejiang Provincial Center for Disease Control and PreventionOTHER_GOV

Collaborators

Xiamen UniversityOTHER

Xiang An Biomedicine LaboratoryUNKNOWN

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