This study was an open-label randomized trial consisting of community-dwelling adults 65 years and older living in Puget Sound area in Washington State. Subjects were enrolled and randomly assigned to receive licensed, 2007-2008 Northern Hemisphere TIV vaccine (Fluzone, lot U2440AA; Sanofi Pasteur) containing concentrations of hemagglutinin of each of A/Solomon Islands/3/2006 (A/H1N1), A/Wisconsin/67/2005 (A/H3N2), and B/Malaysia/2506/2004 (B): 15 ug/0.5 mL by the IM route, 9 ug/0.3 mL by the ID or IM route, or 4.5 ug/0.15 mL given twice by ID route to the nondominant arm. A block randomization scheme (1:1:1:1), stratified by sex, was used. For IM vaccination, 0.3 mL or 0.5 mL of vaccine was removed from a multidose (5 mL) vial through a 25-gauge, 1-inch detachable needle (Becton Dickinson) and was injected into the deltoid muscle at a 90 degree angle to the skin. For ID vaccination, 0.3 mL or 0.15 mL was drawn by a TB syringe through a 25-gauge, 5/8-inch needle (Terumo Medical). The needle was inserted at a 15 degree angle to the skin overlying the deltoid of the arm. The vaccine was slowly injected until all material was expelled and induration appeared. Subjects randomized to the 0.15-mL group received 2 side-by-side ID injections 3 cm apart. Participants returned at 4 weeks to determine postvaccination antibody titers. At this follow-up visit, those assigned to reduced dose IM or ID influenza vaccinations then received full-dose IM influenza vaccination. These participants returned in another 4 weeks to repeat HAI titers. A nonrandomized subset of subjects (based on availability and willingness to participate) returned at 14 days after initial vaccination for T cell assays in an exploratory substudy to examine cellular immune response.