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Electronic Health Record (EHR) Electronic Data Exchange with CT WiZ

Connecticut’s Immunization Information System (CT WiZ)

HL7 Onboarding Process

Blue and White CT WIZ logo the I in Wiz is a syringe


On September 17, 2018, DPH migrated the data from the Connecticut Immunization Registry and Tracking System (CIRTS) into the new CT WiZ! This new Immunization Information System (IIS) enables bi-directional electronic data exchange between your electronic health record (EHR) and CT WiZ.


**Connecticut follows National Standards for Electronic Health Record (EHR) Reporting**


If you are:
  • A provider/clinic who orders vaccines from the Connecticut Vaccine Program (CVP) or COVID-19 Vaccine Provider (CoVP), administers immunizations and is mandated to report immunizations to CT WiZ, and can apply for electronic data exchange with CT WiZ. DPH will send email notifications as evidence of active engagement of each phase as you progress through the onboarding process (registration, testing, production). These email notifications can be used for Promoting Interoperability attestation.

    Note: As CT WiZ accepts bi-directional data exchange with EHRs, if you are attesting to Promoting Interoperability (PI) and you are a CVP or CoVP Provider, you may no longer use the PI exemption letter below to claim an exclusion for Public Health Reporting for Immunizations.

  • A provider/clinic who does not administer immunizations does not report to CT WiZ. If you are attesting to Promoting Interoperability, click here for the exemption letter.
  Promoting Interoperability Attestation Information Click here.

 COVID-19 information click here


Follow the steps below to establish an electronic interface between your EHR and CT WiZ. An interface with CT WiZ can be established for a single clinic (regardless of size) or an organization representing multiple clinics that will report through a single interface. The interface can be set up as uni-directional or bi-directional:

  • Uni-directional is exchanged in one direction, from the EHR to the IIS. Data exchanged refers to Message Submission (VXU) and Acknowledgment (ACK).

  • Bi-directional is data exchanged in two directions, from the EHR to the IIS and from the IIS to the EHR.  Data exchanged refers to Query (QBP) HL7 message submissions that are sent to an IIS and Response (RSP) HL7 message submissions that are returned by an IIS in response to a querying system.

EHR vendors who have onboarded. If your clinic has the same EHR vendor, establishing an interface with CT WiZ will be easier than ever for your clinic. Whether your vendor is on the list or not, just complete the CT WiZ HL7 application form to get started!


 1. Getting Started

Before you start your application, review the following documents.

Onboarding Terms & Acronyms describes common terms that will be used throughout the onboarding process.
The Roles & Responsibilities helps determine who needs to be involved during and after the onboarding process and what they will be doing.
The HL7 Instructions Document walks you through the entire onboarding process.  It describes:
  • The onboarding application
  • Waiting for testing to begin
  • Meetings throughout the process
  • The configuration and connection of your EHR to CT WiZ
  • The testing and validation of HL7 messages
  • Data quality review of HL7 messages
  • Going Live in Production
The Transport Layer Protocol Recommendation Formal Specification provides guidance on connectivity and transport. CT WiZ only accepts submission through SOAP Web Services using the CDC WSDL.

The CT WiZ Immunization Information System HL7 2.5.1 Release 1.5 Local Delta Implementation Guide lists only the areas where CT WiZ deviates from or elaborates on the information contained in the national implementation guidance.


The CVP Patient Eligibility Screening provides guidance on how the clinic should map the vaccine funding program eligibility and funding source for the vaccines in your EHR.


The Vaccines Supplied by CVP provides a list of vaccines supplied by the State of Connecticut. The report contains the vaccine name, brand name, packaging, NDC, manufacturer, CVX code and CT WiZ dropdown selection.


Bi-directional Exchange: Query and Response documentation


The CT WiZ Query and Response Technical Specs provide guidance on how to establish a bi-directional interface with CT WiZ using QBP and RSP.


Troubleshooting an HL7 Interface with CT WiZ


The National HL7 2.5.1 Immunization Messaging Release 1.5 defines what fields and segments the Immunization Information System will and will not accept in an HL7 message. 


The CT WiZ HL7 Segment Overview provides a summary overview of each HL7 segment and if/how it is used in CT WiZ.


The Quick Reference to Fix VXU Errors provides guidance on the most common errors being observed int he VXU message segments.


The ACK Message Guidance for Common Errors in CT WiZ provides information on how to resolve each error, a sample message or segment that has been properly configured or valued and suggested resources where appropriate. 


 2. Complete the Application
Uni-directional Exchange: VXU Messages
Bi-directional Exchange: Query and Response

Ready to apply?  Complete the CT WiZ HL7 Application Form

 3. Application Status

After the application has been submitted, the Connecticut Immunization Program will process the application and contact you if any further information is needed.

If you have any additional questions about the application process, please submit a request to our Helpdesk and include your complete name, organization/clinic name, email and phone number with your detailed question.

Application review and approval typically takes 3-5 business days. Once your application has been approved, you will receive an invitation and additional instructions to begin the testing process.

 4. Testing Phase

Uni-directional Exchange: VXU Messages

When you are ready, "real" patient immunization data (Production) will be submitted in real-time from your EHR system to the CT WiZ QA (Test) environment to test the interface connection and message data quality.  Acknowledgement (ACK) messages will be returned to your EHR system in response. The organization (or their designee) should monitor the ACKs and take action to correct submissions as needed until errors no longer occur.

    Phase 1: Confirm that CT WiZ can accept a test message from your EHR System.

    Phase 2: Validate messages from your EHR that required fields are populated with proper codes.

    Phase 3: Assess data quality of message content to ensure accurate patient data has been sent.

There must be 2 weeks of error and warning free messages before moving into the CT WiZ Production environment.

Bi-directional Exchange: Query and Response

Once the interface has been configured, providers will actively participate in the testing process to ensure correct results and confirm that clinical records are properly updated.


    Phase 1: Testing credentials/URL, connectivity test

    Phase 2: Query and Response configuration and testing preparation

    Phase 3: Workflow testing


Testing for QBP/RSP is typically composed of the following elements:

  1. Query from the provider organization (QBP) to CT WiZ
  2. Response (RSP) from CT WiZ to the provider organization
  3. Update (VXU) from the provider organization to CT WiZ
  4. Acknowledgement (ACK) from CT WiZ to the provider organization

Providers should apply multiple layers of testing:

  • Submit 25-50 records via VXU to query against for a guaranteed response (exact match and forecast)
  • Query using CT WiZ engineered test scenarios (multi-match or too many matches)
  • Query CT WiZ for real patients receiving vaccinations at the clinic (match/no match, VXU update after vaccination)
 5. In Production

When the EHR interface goes into CT WiZ Production, and the clinic is actively exchanging data with CT WiZ, the clinic (or their designee) must continue to review the ACK messages to ensure ongoing submission and data quality. Failed submissions or error messages should be corrected and resubmitted to CT WiZ.

Review the Roles & Responsibilities for who should be handling which tasks.

Follow and complete the Onboarding Go-Live Checklist in order to successfully enter and remain in the CT WiZ Production environment for HL7 messaging.

EHR–HL7 Message Tools in CT WiZ will enable you to:

  • Review HL7 messages that have been sent in their structure, format, data and results.
  • Verify traffic generated by the HL7 messages.
  • View the result of the ACK messages.
  • Learn how to run reports that enable you to view and export information such as:
    • The result of the ACK messages
    • HL7 activity
    • The HL7 facility codes
    • Total messages sent by profile
    • DQA patient vaccination

Connectivity and Transport (SOAP/WSDL)

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