Implement the Immunization Resource

We need to implement the Immunization Resource

At minimum we should support:

• patient
• encounter
• status
• vaccineCode
• occurenceDateTime
• location
• manufacturer
• lotNumber
• expirationDate
• performer

Manufacturer should be represented as a custom extension, since we cannot currently map the Manufacturer into the FHIR-standard Organization resource.

Immunizations are recorded in OpenMRS as a series of obs against a specific encounter. The default set for these observations is CIEL:1421 (IMMUNIZATION HISTORY). Patient, Encounter and Location should be determined from the corresponding properties for the encounter containing the specified observation.

The status will (for now) always be http://hl7.org/fhir/ValueSet/immunization-status|completed

The vaccineCode can be derived from CIEL:984. This should probably be made into a configurable property.

The occurrenceDateTime can be derived from CIEL:1410.

The lotNumber corresponds to CIEL:1420.

The expirationDate corresponds to CIEL:165907.

The performer can be derived from the EncounterProvider (s) associated with the encounter. The appropriate EncounterRole for performer should be specified as a configurable property. For the purposes of this MVP, the performer is always the Administering Provider so the performer.function field should always be http://hl7.org/fhir/ValueSet/immunization-function|AP.