6. Known to have pre-existing diabetes mellitus or an autoimmune disorder. 7. Febrile illness within the last 24 hours or an oral temperature >/= 100.4°F (>/= 38.0°C) prior to IIV or Tdap administration 8. Contraindication to IIV receipt including history of severe allergic reaction after a previous dose of any influenza vaccine; or to a vaccine component, including egg protein 9. Contraindication to Tdap receipt including history of severe allergic reaction after a previous dose of any tetanus toxoid-, diphtheria toxoid-, or pertussis antigen-containing vaccine or encephalopathy within 7 days of administration of a previous dose of a pertussis antigen-containing vaccine that is not attributable to another identifiable cause 10. Arthus-type hypersensitivity reaction following a prior dose of a tetanus toxoid-containing vaccine within the last 10 years 11. Any condition that may interfere with assessment of local injection site reactions, e.g. lymphadenectomy or obscuring tattoos 12. History of Guillain-Barré syndrome within 6 weeks of a prior dose of any tetanus toxoid-, diphtheria toxoid- or pertussis antigen-containing vaccine or influenza vaccine 13. Known or suspected impairment of immunologic function including infection with HIV, hepatitis B or C 14. Use of immunosuppressive or cytotoxic drugs except receipt of oral or parenteral (intravenous, subcutaneous or intramuscular) corticosteroids 30 or more days prior to enrollment. Persons who have used oral or parenteral corticosteroids within 12 months prior to enrollment may be enrolled if the longest course of therapy was less than 14 consecutive days and no dose was given within 30 days of enrollment. Intraarticular, bursal, tendon, or epidural injections of corticosteroids are permissible if the most recent injection was 30 or more days prior to enrolment. Persons applying topically corticosteroid in either upper arm (i.e. injection site) may be enrolled 1 or more days after their therapy is completed. Corticosteroids administered topically at non-injection sites, by inhalation or intranasally are permissible 15. Receipt of any licensed vaccine within 14 days prior to study vaccination or planning receipt of any vaccines (except study vaccines) prior to Visit 7 follow up.