The tradename immunizing agent subset includes tradenames (representing the vaccine brand name) of authorized vaccines and passive immunizing agents (such as immunoglobulins and antitoxins, with ready-made antibodies) in Canada. This subset is a direct extension of the Canadian SNOMED CT Reference Sets developed by Canada Health Infoway. Where available, each SNOMED CT tradename is also linked to its corresponding Health Canada issued unique Drug Identification Number (DIN), lot numbers (assigned by the manufacturer to each vaccine batch), SNOMED CT generic immunization agent concept (representing the non-brand name), vaccine-preventable disease concept (indicating the disease the vaccine protects against), market authorization holder (representing the legal entity authorized by Health Canada for distributing the immunizing agent in Canada), and antigen concept (representing the active ingredient triggering an immune response).