Phase 1 Norwalk Vaccine Study

Randomized, double blind, multi-site, study in healthy adults, comparing safety and immunogenicity of two dosage levels of Norwalk VLP Vaccine with adjuvant/excipients and with placebo controls Primary Objective:

• Safety as determined by occurrence of local intranasal symptoms or other symptoms as reported by a self-administered memory aid for 7 days after each vaccination and hematology, blood chemistry and physical examinations performed by the clinical research staff
• Subjects will also be monitored for Serious Adverse Events (SAEs), and onset of any new medical conditions for 180 days following the last study vaccinations (Day 201). Secondary Objectives Evaluations of immunogenicity as determined by:
• Geometric mean titers and seroconversion rate of serum anti- Norwalk VLP IgG and IgA
• Stimulation of anti-Norwalk VLP IgA antibody secreting cells (ASC)
• Presence of antigen specific memory B-cell response Cells will be collected and stored for possible future evaluation of Norwalk VLP-specific cell-mediated immune (CMI) responses Study Hypothesis: The incidence of adverse events after intranasal Norwalk VLP Vaccine will be the same as the incidence of adverse events after intranasal adjuvant/excipients alone. Norwalk VLP Vaccine and adjuvant/excipients will have a higher incidence of mild to moderate nasal adverse events compared to placebo but similar incidence of other adverse events. Two doses of the 100 µg of Norwalk VLP Vaccine will be more immunogenic than two doses of 50 µg of Norwalk VLP Vaccine. The post-vaccination serum antibody responses, the number of antibody secreting cells (ASC) and IgG and IgA memory B-cell responses directed against Norwalk Virus antigen will be increased after Norwalk VLP Vaccine compared to adjuvant/excipients and to placebo.