HL7^® Reference Guide

VXQ_V01 is a query for vaccination records. It is an older query pattern that uses QRD and optional QRF rather than the newer QBP/RSP immunization query patterns used in many modern IIS guides.

You will usually meet VXQ in legacy immunization interfaces, older registries, or compatibility layers. If you are building a new immunization query interface today, check the receiver's current guide before choosing this message. Many jurisdictions now prefer QBP-based query workflows.

A small VXQ example

What systems do with it

The sender asks an immunization registry or vaccination record system for a patient's vaccination record. The receiver tries to match the patient and returns a response, often VXR_V03 or another profile-specific response. The real work is patient matching, not the two-segment structure.

QRD carries the query definition: time, format, priority, query ID, quantity, subject filters, and what is being requested. QRF can narrow the query with where, when, and patient attributes. In older interfaces, these fields often carry local conventions that must be copied exactly.

Implementation traps

The main trap is assuming a vaccination query is portable just because the message validates. Patient matching rules vary by registry, and query parameters may be constrained beyond the base HL7 structure. A registry may require certain demographic combinations or reject queries that are too broad.

Also plan for multiple matches, no matches, and privacy restrictions. A query response is not always a clean vaccination history. Sometimes it is an acknowledgment, a candidate list, or an error telling the sender to refine the request.

Reference notes

The local v2.5.1 data still includes VXQ_V01, but current CDC immunization guidance points implementers toward the consolidated v2.5.1 immunization guide and modern local IIS profiles. See CDC IIS HL7 guidance before using VXQ in a new interface.