Safety and Immunogenicity of Replication-Competent Adenovirus 4-vectored Vaccine for Avian Influenza H5N1

Inclusion Criteria: * Healthy adults and their healthy adult household contacts. Exclusion Criteria: * Healthcare workers who have direct contact with patients who are immunodeficient, are HIV-positive, have an unstable medical condition, or are under the age of 18. * Childcare workers who have direct contact with children 5 years old and younger. * Resides with Household Contacts who are under the age of 18 or over the age of 65. * Received or plans to receive licensed inactivated 2009 H1N1 influenza vaccine from 14 days prior to 14 days after any study vaccination. * Received or plans to receive any other licensed vaccines from 30 days prior to the first study vaccination until 30 days after the third study vaccination.