Well, if you look it up, it's a Coding System, and it's published by CDC here. But in fact, it does both. It identifies the concepts of Vaccine Manufacturers, but those are also "Entities" in V3 speak, actual things you could put your hands on evidence of (e.g., articles of incorporation), if still conceptual. So they also serve as identifiers.
When I used to teach CDA (and V3) regularly, I would explain that codes are simply identifiers for concepts. I ran across this while working on V2 to FHIR because FHIR Immunization resources treat the manufacturer of an immunization as a first-class resource, an organization, but HL7 V2 treats it as a code from a table in a CE or CWE datatype (depending on HL7 version).
What is one to do? Well, it's actually pretty straightforward. I downloaded the CVC MVX codes from the link above, write them into a coding system with code being the MVX code, and display being the Manufacturer name. When I create the Organization, name gets the value of display, and identifier gets the value of code, and system remains the same. It works like a charm.
Keith
