This is the CodeSystem that contains all the codes in AdverseEventCategory (http://terminology.hl7.org/CodeSystem/adverse-event-category) and AdverseEventCategory (http://terminology.hl7.org/CodeSystem/adverse-event-category). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: CodeSystem 5b1132b8-51e9-46ac-8efa-9d1c907d9515-551
This code system http://hl7.org/fhir/comparison/CodeSystem/5b1132b8-51e9-46ac-8efa-9d1c907d9515-551
defines codes, but no codes are represented here