Effects of Age on Response to the 2009 H1N1 Virus Vaccine

Inclusion Criteria: * No prior history of infection with novel H1N1 virus or immunization with novel H1N1 vaccine documented by a laboratory * Female participants must not be capable of becoming pregnant or take steps to prevent pregnancy from 30 days before enrollment to 30 days after receiving the study vaccine * In good health, as determined by medical history and targeted physical examination * Able to understand and comply with the planned study procedures, including being available for all study visits Exclusion Criteria: * Pregnancy * Previous history of vaccination against novel H1N1 virus or a laboratory documented history of previous novel H1N1 infection * Immunosuppressed as a result of an underlying illness or treatment with immunosuppressive or cytotoxic drugs or use of anticancer chemotherapy or radiation therapy within the preceding 36 months * Active neoplastic disease (excluding nonmelanoma skin cancer or prostate cancer that is stable in the absence of therapy) or a history of any hematological malignancy. For this criterion, "active" is defined as having received treatment within the past 5 years. * Long-term (greater than 2 weeks) use of oral or parenteral steroids or high-dose inhaled steroids (greater than 800 mcg/day of beclomethasone dipropionate or equivalent) within the 6 months prior to study enrollment (nasal and topical steroids are allowed) * Received immunoglobulin or another blood product within the 3 months prior to enrollment in this study * Received an inactivated vaccine within 2 weeks or a live vaccine within 4 weeks prior to enrollment in this study or plans to receive another vaccine within the next 28 days * Has an acute or chronic medical condition that, in the opinion of the investigator, would render vaccination unsafe or would interfere with the evaluation of responses. * Has had an acute illness or an oral temperature greater than 99.9°F (37.7°C) within 3 days prior to enrollment or vaccination. Subjects who had an acute illness that was treated with symptoms resolved are eligible to enroll as long as treatment is completed and symptoms are resolved more than 3 days prior to enrollment. * Currently participating or plans to participate in a study that involves an experimental agent (vaccine, drug, biologic, device, blood product, or medication), has received an experimental agent within 1 month prior to enrollment in this study, expects to receive another experimental agent during participation in this study, or intends to donate blood during the study period * History of alcohol or drug abuse in the 5 years prior to enrollment * Has a known human immunodeficiency virus (HIV) or hepatitis B or C infection * Has a previous history of Guillain-Barré syndrome * Allergic to eggs or egg proteins, gentamicin, gelatin, or arginine or has experienced life-threatening reactions to previous influenza vaccination * Has any other condition that would, in the opinion of the site investigator, place the participant at an unacceptable risk of injury or render the participant unable to meet the requirements of the protocol