The purpose of this study is to demonstrate the safety and immunogenicity of an oral vaccine to prevent avian influenza. Volunteers will receive either one or two doses of research vaccine or placebo as part of this study.

Inclusion Criteria:

• In good health as established by medical history, physical examination and laboratory testing at the time of enrollment.

Exclusion Criteria:

• Has had any other vaccines within the past 8 weeks.
• Has had prior H5 avian influenza investigational vaccine.
• Current history of chronic alcohol consumption and/or illicit and/or recreational drug use.
• History of autoimmune related disease.
• History of any confirmed or suspected immunodeficient or immunosuppressive condition (no congenital or acquired condition that impedes normal immune response, no concurrent immunosuppressive therapy).
• Positive serology for HIV, HCV, or HBV.
• Previous serious reactions to vaccination such as anaphylaxis, respiratory problems, hives or abdominal pain.
• History of irritable bowel disease or other inflammatory digestive or gastrointestinal conditions that could affect the intended distribution or safety evaluation of an orally administered vaccine targeting the mucosa of the small intestine.
• Use of proton pump inhibitors (Nexium, Prilosec) that substantially increases stomach pH.
• Stool sample with occult blood at baseline exam