This is the CodeSystem that contains all the codes in US Public Health CodeSystem - Usage Context (http://hl7.org/fhir/us/ph-library/CodeSystem/us-ph-codesystem-usage-context) and US Public Health CodeSystem - Usage Context (http://hl7.org/fhir/us/ph-library/CodeSystem/us-ph-codesystem-usage-context). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: CodeSystem 52ca7194-343c-4909-957a-337291b688fc-20
This code system http://hl7.org/fhir/comparison/CodeSystem/52ca7194-343c-4909-957a-337291b688fc-20 defines codes, but no codes are represented here