CITF Harmonization and Validation Code – Release v1.0

The code was developed using R version 4.5.0. File paths and database connection parameters are represented by configurable placeholders and must be adapted to the user’s local environment. Database credentials, internal server addresses, and participant-level data are not included in the repository.

Validation rules The repository includes documentation of the rule-based checks applied during harmonization and validation. The checks are organized into six stages: data-ingestion checks; schema and Core Data Element alignment; serology metadata and plausibility checks; internal-consistency checks; cross-study comparability assessment; and documentation, provenance, and version control. For each rule, the documentation describes the acceptance criterion and the action taken when the criterion is not met.

These procedures constitute dataset-level quality control. They do not represent laboratory re-testing or independent biological validation of assay performance. Metadata schemas The repository includes the CITF Core Data Element schemas for the baseline questionnaire, vaccination, and serology harmonized domains.

The schemas define the relevant variables, labels, value types, units, and permitted categories. Supporting serological assay metadata and code lists are included where relevant. Study-specific source variables are mapped to the CITF Core Data Elements according to defined rules for recoding, non-negativity, range constraints, date-component validation, duplicate handling, and assessment of the chronological consistency of repeated events.

Study-reported event and vaccination-dose numbers are retained and are not reassigned solely on the basis of event dates. Data management and access Original study datasets were transferred through McGill University’s secure file-exchange environment, processed using the R-based harmonization workflow, and stored in a PostgreSQL relational database to support structured data management and release versioning. Access to restricted participant-level datasets requires a formal request to the CITF Data Access Office and is subject to applicable institutional approvals, consent conditions, governance requirements, and data-sharing agreements.

Release: v1.0 Release date: February 1, 2026