Health and Wellness

Immunization Query Response Aggregate Measures for Multiple Matches Report

Two health professionals standing at a workstation with masks on.


In February 2020, the Immunization Integration Program (IIP) Executive Committee identified four areas of focus from over 30 prioritized issues for improving immunization interoperability, information sharing and management. The collaborative selected a workstream to address standardized workflow, messaging and business rules related to multiple patients found in the IIS in response to a query. Queries to an immunization information system (IIS) for a patient may result in a variety of responses. To address these issues, a workgroup was formed to discuss challenges and develop potential solutions. Upon the first workgroup meeting, it became apparent that in addition to reviewing multiple match candidates, clinicians have similar challenges when reviewing low confidence matches with single match candidates. Both outcomes are communicated using the same type of HL7 message (Z31 profile ) and include patient identifiers and demographics, but exclude immunization histories and forecasts. Therefore, the workgroup’s scope expanded to include “inexact matches”—both those with multiple match candidates and those with a single low confidence match candidate. In addition to inexact matches, a query to an immunization information system (IIS) may return a single high confidence match, no matches, too many matches or a match to a patient’s record that may not be returned due to a protection status.

The handling of query responses indicating inexact matches remains inconsistent and can result in the inability of clinicians to provide accurate immunization recommendations. Inexact matches also add burden to provider workflow, as re-query is required to obtain a patient’s immunization history and forecast. This ultimately impacts the effectiveness of patient care. For both responding systems (typically IIS) and querying systems (typically electronic health record (EHR) systems), failure to efficiently manage inexact match candidates and correctly match patients can result in gaps and, in certain situations, errors in a patient's immunization history. For example, if the provider initiates a query that results in an inexact match, the provider may not be able to re-query with additional match information. Either the data is not available or obtaining more data may cause unintended burden. As a result, the accurate history or history and forecast may not be available at the time of the visit. In other cases, if several patients are returned and the EHR lacks the ability to manage them, the EHR responds as if no patient was found, slowing down the provider workflow.

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