> For the complete documentation index, see [llms.txt](https://guides.ohie.org/arch-spec/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guides.ohie.org/arch-spec/dev-1/introduction/case-reporting-new-section-needs-to-go-in-alpha-order/request-vaccine-status.md).

# Retrieve Health Certificate

A verifier (point-of-care application or any authorized application outside of the HIE) can use this transaction to verify a Digital Documentation COVID Certificate (DDCC) Immunization event. This may include COVID immunizations and negative tests.

| **Workflow Maturity**         | <p><img src="https://lh6.googleusercontent.com/Kxkqfa92YGW3mIOmWio0Twi4YLMA92z6mL1MuFzkx4AWS5CX5zbzWid5z4p2W-e6O66llKpaU0r6lzwyXfhbIiWmkVEuPDy6stX5x5L8uC2DkEXs6qUFX-7xxXTlb9hbkg" alt=""></p><p><strong>Newly Defined</strong></p> | <ul><li><strong>Workflow is defined by WHO and has OpenHIE ARB approval</strong></li><li><strong>Initial implementations are being considered.</strong></li></ul>                                                                                                                                                                                                                                                  |
| ----------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Standards                     |                                                                                                                                                                                                                                     | <ul><li>The Retrieve Health Certificate transaction is based on <a href="https://profiles.ihe.net/ITI/MHD/ITI-68.html">MHD's Retrieve Document transaction \[ITI-68]</a>. It can be used to verify the contents of a DDCC Immunization event.</li></ul>                                                                                                                                                            |
| Assumptions and Prerequisites |                                                                                                                                                                                                                                     | <ul><li>The appropriate trust agreements and processes have been put in place for the Verifier to receive the certificate.</li><li>The appropriate transactions denoting health certificate status have been stored. This may include saving a vaccine or a lab test event to a shared health record via <a href="/pages/-Me5LoFUIByseApmjarp">Save Patient-level Clinical Data Workflow</a>.</li></ul>            |
| Actors                        |                                                                                                                                                                                                                                     | <ul><li>Verifier (External System) - External system or Point-of-care system requesting the vaccine status.</li><li>IOL - The interoperability layer that secures and orchestrates the exchange of information (see OHIE Interoperability layer)</li><li>SHR (or Vaccine Service Repository) - The shared health record that serves as a centralized data store for patients’ longitudinal health record</li></ul> |

## Interaction Description

The Interaction Description is stored in the ["Retrieve Health Certificate Reference" in the WHO FHIR IG](https://worldhealthorganization.github.io/ddcc/transactions.html).

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References: [WHO DDCC Workflows](https://worldhealthorganization.github.io/ddcc/workflows.html)
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