Assessment of an Oral Influenza B Vaccine Tablet (VXA-BYW.10) Following Single Dose Administration in Healthy Adults

The study will enroll 54 subjects in four cohorts. All subjects will receive a single administration of VXA-BYW.10 at a low dose, a high dose or placebo. Two sentinel groups will enroll 3 subjects each in an open-label manner (Cohorts 1 and 3) to receive VXA-BYW.10 prior to enrolling either of the randomized, controlled cohorts (Cohorts 2 and 4). Within the double-blinded Cohorts (2 and 4), placebo subjects will receive the same number of tablets as the vaccine subjects in that Cohort. Subjects will be enrolled and dosed in the low dose groups prior to initiation of dosing in the high dose group. Cohort 1: 3 subjects at low dose; Cohort 2: 16 subjects at low dose and 8 placebo; Cohort 3: 3 subjects at high dose; Cohort 4: 16 subjects at low dose and 8 placebo Subjects will be followed for 28 days post vaccination for preliminary immunogenicity. Subjects will continue to be followed for 1 year post-vaccination for long term safety.