Norovirus infections are a leading cause of sporadic and epidemic gastroenteritis across all age groups worldwide. This study is designed as a standard double-blind placebo-controlled single administration, dose ranging study to evaluate the safety and immunogenicity of 2 different doses of VXA-GII.4-NS plus VXA-G1.1-NN (high and medium dose administered orally for the prevention of Norovirus infection), compared with a placebo.~This study will enroll 10 sentinel subjects in an open label period (dosing staggered to not-more-than 2 subjects per 24 hours) and randomize 125 subjects in three arms.~The first 10 sentinel subjects will receive the open label high dose of active vaccine. If no dose-related toxicities are observed, and upon the recommendation of the SMC following review of safety data, subjects will be randomized in a 2:2:1 ratio to one of the 3 study arms to receive active vaccine or placebo. After vaccination on Day 1, the study will include an Active Study Period that runs through 4 weeks after administration (Day 29), and a Follow-up Period of one year for safety and duration of immune response.
This study is designed to evaluate the safety and immunogenicity of two monovalent Norovirus (NoV) oral tableted vaccine candidates, VXA-G1.1-NN and VXA-GII.4-NS co-administered (bivalent delivery) against a matching placebo arm. Bivalent GI.1 and GII.4 vaccines are being investigated for the prevention of noroviral gastroenteritis caused by norovirus GI.1 and GII.4.