ImmunizationRecommendation is currently modeled as a resource to represent an immunization forecast from a clinical decision support service which might be performed and sent from within the EHR software, from an immunization registry (Immunization Information System) or a third party, web-based query or a SMART app.

However, there is no reference in FHIR about how to manage an order for an immunization or a recommendation from a provider to a patient that an immunization is required or expected. MedicationRequest provides such a possibility using the .intent _metadata element in which the * _plan * element is most consistent with a recommendation to the patient and the order element is most consistent with an * order *. ProcedureRequest and ReferralRequest are similarly modeled. And, in FHIR STU 4, there is consideration to merge such requests into ServiceRequest. There are steps within a clinical workflow in which a provider receives the forecast (the current ImmunizationRecommendation) from which the provider orders the immunization/vaccine. In some cases, the order is a prescription filled by a pharmacist and the patient picks up the immunization and returns to the physician office to have it administered (or has it administered at the pharmacy). The order should include metadata elements not present in the ImmunizationRecommendation resource: orderQuantity and route of anticipated administration, and source (i.e., should the immunization come from specific guarantee program inventory or should it come from non-guarantee program inventory (or other possible inventory designations).

Bottom line - Immunization should address modeling similar to other resources, especially medication or at the very least, clear guidance should be included about which resource to use when. (E.g., for immunization request, use MedicationRequest resource) and assure the referenced resource includes the metadata elements requried to successfully met the use case.