HL7 VXX_V02 Vaccination Query Multiple Matches Response

The old vaccination query answer that says: I found candidates, but not one clean record.
HL7 message structure VXX_V02 groups and segments from HL7 v2.5.1 Hide structure

These are the generated groups and segments for the version selected at the top of the page. The article explains the workflow, and this panel follows the chosen HL7 version.

Message Structure

SegmentNameRequiredRepeatable
MSH
 Message Header Yes No
MSA
 Message Acknowledgment Yes No
SFT
 Software Segment No Yes
QRD
 Original-Style Query Definition Yes No
QRF
 Original style query filter No No
VXX_V02.PATIENT
 Patient group Yes Yes
PID
 Patient Identification Yes No
NK1
 Next of Kin / Associated Parties No Yes

VXX_V02 is a legacy vaccination query response used when a vaccination query finds multiple possible patient matches. Instead of returning the vaccination history, the receiver returns candidate patient identities so the requester can refine the query or ask a human to choose.

You will mostly see this around older VXQ/VXR immunization workflows, compatibility layers, or historical interfaces. Newer immunization implementations usually use profile-specific QBP/RSP patterns.

A small VXX V02 example

MSH|^~\&|IIS|STATE|EHR|CITYCLINIC|20260715172030||VXX^V02^VXX_V02|VXX00001|P|2.5.1 MSA|AA|VXQ00001 QRD|20260715172000|R|I|VXQ00001|||5^RD|Smith^Jamie|VXI^Vaccine Information^HL70471|T QRF|IIS|20200101|20260715|Smith^Jamie|20190514|F PID|1||100001^^^IIS^SR||Smith^Jamie^^^^^L||20190514|F NK1|1|Smith^Alex|MTH PID|2||100778^^^IIS^SR||Smyth^Jamie^^^^^L||20190514|F NK1|1|Smyth^Alex|MTH

What systems do with it

The registry or immunization system receives a vaccination query but cannot safely choose one patient. It returns an acknowledgment plus the original query context and a repeating set of candidate PID groups. The requester can then refine the search or present the candidates for manual review.

This response should not be mistaken for a vaccination record. A VXX_V02 candidate list normally carries matching patient identities, not immunization administrations.

How to read the structure

MSH identifies VXX^V02^VXX_V02. MSA acknowledges the original query. QRD and optional QRF echo the query definition and filters.

The repeating patient group contains PID and optional NK1. Those groups are the candidate matches. In a real interface, the receiver's guide should define how many candidates can be returned and which fields are safe to display.

Implementation traps

Do not automatically pick the first PID. Multiple-match responses are deliberately asking for disambiguation. If the requester chooses too aggressively, it can attach another person's immunization history to the chart.

Also watch privacy rules. Candidate lists can expose demographic data for people who are not the patient the user intended. Many modern profiles put tighter controls around this workflow.

Reference notes

HL7 v2.3 describes VXX_V02 as the response to a vaccination query returning multiple PID matches. See the HL7 event page for V02. For new IIS work, also compare the receiver's current immunization guide before choosing this older message.