Around the world, various different coding systems are used for immunizations:

 <status value="active"/> <experimental value="false"/> <publisher value="HL7 FHIR"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> </contact> <description value="This identifies the vaccine substance administered - CVX codes."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <compose> <include> <system value="http://hl7.org/fhir/sid/cvx"/> </include> <include> <system value="urn:oid:1.2.36.1.2001.1005.17"/> </include> </compose> </ValueSet>