Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content

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] guide.

Patient Level Deduplication

For more specific information on patient level deduplication including best practices and test cases, please visit the EHR-IIS Interoperability Expert Panel page.

If you have any questions, please send them via email to