Type Alias: ImmunizationRecordOrigin

ImmunizationRecordOrigin = "administered" | "historical"

Whether an Immunization records a dose that was administered by the reporting system or is historical information sourced from elsewhere, derived conservatively from RXA-9.1 against HL7 Table NIP001 (Immunization Information Source, CDC v2.5.1 Immunization Messaging IG):

• "administered": RXA-9.1 is exactly "00" (New immunization record).
• "historical": RXA-9.1 is "01".."08" (any "Historical information …" source).

Fail-safe: this is OMITTED (never guessed) when RXA-9 is absent or carries a code outside the NIP001 administered/historical set. The raw RXA-9 claim is always preserved verbatim on Immunization.informationSource, so a consumer can inspect the original code even when recordOrigin is undefined. The distinction matters because an IIS de-duplicates a historical report differently from a dose it believes was administered: guessing corrupts the registry.