WHO Immunization Implementation Guide, published by World Health Organization (WHO). This guide is not an authorized publication; it is the continuous build for version 0.1.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/WorldHealthOrganization/smart-immunizations and changes regularly. See the Directory of published versions

Data Models and Exchange

This section contains the data models and data exchange protocols with actors and transactions defined. It is part of the L3 machine-readable knowledge representation.

The pages included in this section are described below.

• ​Actors - A list and description of software or human entities that interact with the system, derived from business requirements defined in the L2.
• Sequence Diagrams - Sequence diagrams depicting the interactions between system actors, in order, derived from business processes in the L2.
• Transactions - A defined list of system transactions at an atomic level for each actor along with narrative, capability statements, structure definition, questionnaires, document bundles and composition. It may also refer to transactions in other implementation guides.
• ​Logical Models - A StructureDefinition resource that describes data element definitions and their associated rules of usage, derived from the data dictionary in the L2.
• Indicators and Measures - A thematic list of indicators defined in the implementation guide that link to L1 and L2 guidance documents.

Design Documentation -DRAFT-

The documentation below details how to use this IG to execute the decision logic and the resources required to do so including PlanDefinitions, ActivityDefinitions, ValueSets, and Libraries.

PlanDefinitions

Each antigen in the WHO recommendations for routine immunization - summary tables has been represented as a FHIR PlanDefinition conformant to the FHIR Clinical Practice Guidelines Implementation guide CPG-ComputablePlanDefinition. For example, there is a PlanDefinition for Hepatitis A, Measles, etc. The intention behind this design is for each implementation to utilize only the antigens that are required for their national/local context, as many countries have national vaccine routines, which may leverage the WHO guidance. The aim of this content was to be adaptable for those contexts.

These PlanDefinitions can be found in the Artifact Index

ActivityDefinitions

To represent the activities that need to be carried out, this implementation guide follows the workflow patterns established by the base FHIR specification. Each antigen represented as a PlanDefinition will be processed to produce ActivityDefnitions conform to the FHIR Clinical Practice Guidelines Implementation guide CPG-ActivityProfiles.

In particular, processing the PlanDefinition with the $apply operation FHIR-Workflow will result in the creation of an CPG-ImmunizationActivity

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As part of the implementation the country specific EIR (Electronic Immunization Registry) will need to fill in the ActivityDefinition.product[x]. It is not possible for this IG to recommend a specific product. There are limitations of supply chain, country specific needs, and other issues which cannot be captured and generalized to accomodate all specific use cases.

For example, Cholera has 3 SNOMED Codes and 4 ATC Codes.

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FHIR Library

The FHIR Library contains a base64 encoded CQL library which represents the decision logic as a series of boolean clauses. Each PlanDefinition and Measure will reference a Library from which each decision point can be made and specify which expression from the CQL is used to trigger a decision in PlanDefinition or where to retrieve data to create the MeasureReport in the Measure, repsectively.

ValueSets

Many of the ValueSets used in this IG are from CPG on FHIR and the IPS. There are a number of generated ValueSets based on the user scenarios detailed in this IG.

There is one exception to that format which is the vaccine libraries, which map the codes between a variety of different systems including SNOMED GPS and WHO ATC in order to allow implementers to search for any vaccine which might be applicable to their user. More details on this approach is provided below.

Vaccine Library

The ValueSets include a vaccine list of many codes which may be found in a patient record to see if the patient has been vaccinated with a particular antigen. For example Diptheria is often paired with Tetanus and Pertussis, it can also be paired with influenza or polio. Therefore a patient record may have an Immunization event recorded where they received a combo vaccine, which covers multiple antigens. To run decision support on a specific antigen the vaccine library contains a selection of products which might cover Diptheria. In the CQL these are used akin to an array of potential codes which may be present in the Immunization resource when calculating an indicator or decision support event.