This randomized, double-blinded, placebo-controlled, dose-ranging, Phase I/II, influenza study will compare the safety, reactogenicity, and immunogenicity of increasing doses of monovalent subvirion influenza A/H7N7 virus vaccine administered by intramuscular (IM) injection to healthy adults. A total of 125 healthy adults ranging from 18 to 40 years old will be enrolled at one site for this study. The subjects will be randomized to receive saline placebo or 7.5, 15, 45, or 90 mcg of the influenza A/H7N7 vaccine by intramuscular (IM) injection in an approximate 1:1:1:1:1 ratio (N=25/vaccine dose group and 25 in the placebo group). Subjects will receive 2 doses separated by approximately 28 days. Subjects will be observed in the clinic for a minimum of 30 minutes after inoculation. All subjects will maintain a memory aid to record oral temperature and systemic and local adverse events (AEs) for 7 days after each immunization. Subjects will be contacted by telephone 1-3 days after vaccination to assess for the occurrence of AEs, and they will return to the clinic between Day 8 and 12 for AE and concomitant medication assessment, a targeted physical examination (if indicated), and review of the memory aid. Serum for immunogenicity evaluations will be obtained for subjects prior to the first vaccination, at Day 28 prior to the second vaccination, and on Days 56 and 208. A Safety Monitoring Committee (SMC) will review available 7 day safety data at approximately Day 20 following the first subject vaccination before administering the second dose of vaccine to any subjects. The primary objectives of the study will be: to determine the dose-related safety of subvirion inactivated H7N7 vaccine in healthy adults; to determine the dose-related immunogenicity of subvirion inactivated H7N7 vaccine in healthy adults approximately 1 month following receipt of 2 doses of vaccine; and to provide information for the selection of the best dose levels for further studies. The secondary objective will be to evaluate the dose-related immunogenicity and the percent of subjects responding approximately 1 and 7 months after the first vaccination. The primary endpoints are: adverse event (AE) or serious adverse event (SAE) information (solicited in-clinic and via memory aids, concomitant medications, and periodic targeted physical assessment); the proportion of subjects in each dose group achieving a serum neutralizing antibody titer of greater than or equal to 40 against the influenza A/H7N7 virus 28 days after receipt of the second dose of vaccine (approximately Day 56); geometric mean titer (GMT) and frequency of 4-fold or greater increases in neutralizing antibody titers in each group 1 month after receipt of each dose, and 7 months after receipt of the first dose of vaccine; and GMT and frequency of 4-fold or greater increases in serum hemagglutination inhibition (HAI) antibody titers in each group 1 month after receipt of each dose, and 7 months after receipt of the first dose of vaccine. Participants will be involved in study related procedures for approximately 7 months. This study is linked to DMID protocol 07-0060.