Question: Answer: Your first step in choosing the correct code is to look at the administration route. For flu pandemic vaccine that is intranasally administered, use 90664 (Influenza virus vaccine, pandemic formulation, live, for intranasal use). There are three intramuscular flu pandemic codes. For IM flu pandemic products, check the vaccine's specifics: Don't miss: 90644 -- Meningococcal conjugate vaccine, serogroups C & Y and Hemophilus influenza B vaccine, tetanus toxoid conjugate (Hib-MenCY-TT), 4 dose schedule, when administered to children 2-15 months of age, for intramuscular use. Since 90644 contains three components, using the CPT 2011 component based vaccine administration with counseling codes, you'll assign 90460 and +90461 x 2 when 90644 is administered.