Message type

Unsolicited vaccination record update

Transmits an unsolicited vaccination record update to an immunization registry. The PID segment identifies the patient and RXA segments carry the administered vaccine details. Public health registries and clinical systems consume this.

30segments

9required

4groups

v2.9HL7 version

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'VXU^V04^VXU_V04|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'RXA|0|1|20260701||08^HepB^CVX|1|mL|IM'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
substance = msg.rxa.administered_code
amount = msg.rxa.administered_amount

Python examples

Build and parse VXU^V04 messages in Python

How to construct, send, receive, and extract fields from real-world VXU^V04 messages.

Parse an incoming VXU^V04 message

Demonstrates receiving and extracting key fields from a unsolicited vaccination record update transaction

# Zato
from zato.hl7v2 import HL7Message

# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
      'VXU^V04^VXU_V04|MSG001|P|2.9\r' \
      'PID|1||MRN-10045||SMITH^JOHN||19850315|M\r' \
      'RXA|0|1|20260701||08^HepB^CVX|1|mL|IM'

# .. parsed into a Python object ..
msg = HL7Message.parse(raw)

# .. whose fields we can now access.
name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth
substance = msg.rxa.administered_code
amount = msg.rxa.administered_amount

Tutorials

Learn by building

Step-by-step guides for working with HL7 v2 in Zato.

MLLP

Receive and parse HL7 v2 messages

Set up an MLLP channel, parse incoming messages, and respond with acknowledgments.

Start tutorial Build

Build and send HL7 v2 messages

Construct HL7 v2 messages from scratch using typed segment classes and send them over MLLP.

Start tutorial

FAQ

Frequently asked questions

Use the HL7v2 message parser to extract the typed structure. The parsed message gives you direct access to every segment and field by name.

from zato.hl7v2 import HL7Message

raw = 'MSH|^~\&|SENDER|FACILITY|RECEIVER|DEST|20260401120000||VXU^V04^VXU_V04|MSG00001|P|2.9\rPID|1||MRN-10045||JOHNSON^SARAH^M||19880612|F|||100 Oak Lane^^Portland^OR^97201\rPD1|||Family Health Clinic^^12345\rPRT|1||AT^Attending||1234^CHEN^DAVID^L^^^MD\rNK1|1|JOHNSON^MICHAEL|SPO^Spouse|100 Oak Lane^^Portland^OR^97201|5035551234\rGT1|1||JOHNSON^SARAH^M||100 Oak Lane^^Portland^OR^97201|5035559876'
msg = HL7Message.parse(raw)

name = msg.pid.patient_name
dob = msg.pid.date_time_of_birth

Beyond the mandatory MSH header, the required segments are: PID, PV1, IN1, OBX, ORC, TQ1, RXA, OBX. Optional segments provide additional detail when available.

Zato connects to any system that speaks HL7v2 over MLLP or FHIR over REST. This includes Epic, Cerner, Meditech, Allscripts, and other EHR platforms.

Yes, Zato has built-in MLLP support for sending and receiving HL7v2 messages. MLLP channels handle the framing protocol automatically.

Zato supports HL7 v2.9, which is backward compatible with earlier versions including v2.3, v2.5, and v2.7. Standard segments and datatypes are available as typed Python classes.

Yes. Zato handles both HL7v2 and FHIR natively, so you can parse v2 messages and build FHIR resources with IG-specific extensions in the same service. Typed Python classes are available for both protocols, including extensions from US Core, UK Core, Da Vinci, and other Implementation Guides.

Reference

VXU^V04 segment composition

Segments that make up the VXU^V04 message, in order. Groups are shown with their child segments.

#	Segment	Usage	Repeats	Description	Group
1	`MSH`	Required	No	Message header	-
2	`ARV`	Optional	Yes	Access restriction	-
3	`SFT`	Optional	Yes	Software segment	-
4	`UAC`	Optional	No	User authentication credential	-
5	`PID`	Required	No	Patient identification	-
6	`PD1`	Optional	No	Patient additional demographic	-
7	`PRT`	Optional	Yes	Participation information	-
8	`NK1`	Optional	Yes	Next of kin / associated parties	-
9	`ARV`	Optional	Yes	Access restriction	-
10	`PV1`	Required	No	Patient visit	PATIENT_VISIT
11	`PV2`	Optional	No	Patient visit - additional info	PATIENT_VISIT
12	`PRT`	Optional	Yes	Participation information	PATIENT_VISIT
13	`ARV`	Optional	Yes	Access restriction	PATIENT_VISIT
14	`GT1`	Optional	Yes	Guarantor	-
15	`IN1`	Required	No	Insurance	INSURANCE
16	`IN2`	Optional	No	Insurance additional info	INSURANCE
17	`IN3`	Optional	No	Insurance additional info - certification	INSURANCE
18	`OBX`	Required	No	Observation result	PERSON_OBSERVATION
19	`PRT`	Optional	Yes	Participation information	PERSON_OBSERVATION
20	`NTE`	Optional	Yes	Notes and comments	PERSON_OBSERVATION
21	`ORC`	Required	No	Common order	ORDER
22	`PRT`	Optional	Yes	Participation information	ORDER
23	`TQ1`	Required	No	Timing / quantity	ORDER
24	`TQ2`	Optional	Yes	Timing / quantity relationship	ORDER
25	`RXA`	Required	No	Pharmacy / treatment administration	ORDER
26	`PRT`	Optional	Yes	Participation information	ORDER
27	`RXR`	Optional	No	Pharmacy / treatment route	ORDER
28	`OBX`	Required	No	Observation result	ORDER
29	`PRT`	Optional	Yes	Participation information	ORDER
30	`NTE`	Optional	Yes	Notes and comments	ORDER

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Open source In Python