Evaluating the Safety and Immune Response to a Live H7N9 Influenza Virus Vaccine Followed by an Inactivated H7N9 Influenza Virus Vaccine, Given at Varying Intervals

Inclusion Criteria: * Adult males and non-pregnant females between 18 years and 49 years of age, inclusive. Children will not be recruited or enrolled in this study because they are not in the apparent risk group, for safety considerations, and because of the need for isolation. * General good health, without significant medical illness, physical examination findings, or significant laboratory abnormalities as determined by the investigator * Agree to storage of blood specimens for future research * Available for the duration of the trial * Willingness to participate in the study as evidenced by signing the informed consent document * Female participants of childbearing potential must agree to use effective birth control methods for the duration of the study (for example, pharmacologic contraceptives including oral, parenteral, and transcutaneous delivery; condoms with spermicide; diaphragm with spermicide; intrauterine device; abstinence from heterosexual intercourse; surgical sterilization). All female participants will be considered being of childbearing potential except those who have undergone hysterectomy and those in whom menopause occurred at least 1 year prior to the study. Exclusion Criteria: * Pregnancy, as determined by a positive human choriogonadotropin (beta-HCG) test * Currently breastfeeding * Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, or renal disease by history, physical examination, and/or laboratory studies including urine testing * Behavioral or cognitive impairment or psychiatric disease that in the opinion of the investigator affects the ability of the participant to understand and cooperate with the study protocol * Previous enrollment in an H7 influenza vaccine trial or in any study of an avian influenza vaccine * Seropositive to the H7N9 influenza A virus (serum HAI titer greater than 1:8) * Positive urine drug toxicology test indicating narcotic use/dependency * Have medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 12 months * Other condition that in the opinion of the investigator would jeopardize the safety or rights of a participant in the trial or would render the participant unable to comply with the protocol * History of anaphylaxis * Allergy to oseltamivir as determined by participant report * Current diagnosis of asthma or reactive airway disease (within the past 2 years) * History of Guillain-Barré Syndrome * Positive enzyme-linked immunosorbent assay (ELISA) and confirmatory test (e.g., Western blot or HIV-1/HIV-2 differentiation assay) for human immunodeficiency virus-1 (HIV-1) * Positive ELISA and confirmatory test (e.g., recombinant immunoblot assay) for hepatitis C virus (HCV) * Positive hepatitis B virus surface antigen (HBsAg) by ELISA * Known immunodeficiency syndrome * Use of corticosteroids (excluding topical preparations) or immunosuppressive drugs within 30 days prior to vaccination * Receipt of a live vaccine within 4 weeks or a killed vaccine within 2 weeks prior to study vaccination * History of asplenia * Body mass index (BMI) greater than 40 * Receipt of blood or blood-derived products (including immunoglobulin) within 6 months prior to study vaccination * Current smoker unwilling to stop smoking for the duration of the study. More information on this criterion is available in the protocol. * Travel to the Southern Hemisphere within 14 days prior to study vaccination * Travel on a cruise ship within 14 days prior to study vaccination * Receipt of another investigational vaccine or drug within 30 days prior to study vaccination * History of hypersensitivity to any component of the investigational product including egg or egg protein, or serious, life threatening, or severe reactions to previous influenza vaccinations * Individuals who use intranasal medications chronically * Receipt of antiviral therapy or antiviral agents within 48 hours prior to receipt of investigational product