IIS Deduplication

Deduplication of immunization records is a two-fold problem that includes deduplication at the demographic/patient level (e.g., two records describe the same patient) and deduplication at the vaccination event level (e.g., two records describe the same immunization). Resources have been developed to assist with both aspects of deduplication.

Vaccine Level Deduplication

For best practices regarding vaccine level deduplication, see the Modeling of Immunization Registry Operations Workgroup (MIROW) Vaccination Level Deduplication in Immunization Information Systems [102 pages]external icon guide.

Patient Level Deduplication

Patient deduplication is the process of removing redundant patient records from a database, preventing fragmented and duplicate information from being processed and ensuring that updates and queries apply to the correct record.

Inconsistencies in determining which records represent the same patient, as well as errors in combining patient’s immunization records, negatively affect the overall data quality and usefulness of Immunization Information Systems (IIS). The following resource was developed by subject matter experts in the field of patient deduplication and matching.

If you have any questions, please send them via email to iisinfo@cdc.gov.

Page last reviewed: June 7, 2019