Vaxart, Inc. announced that it has shown for the first time in clinical trials that its oral tablet vaccine platform successfully boosted immune responses in subjects previously vaccinated with a Vaxart oral vaccine more than a year earlier. Vaxart is a clinical-stage biotechnology company developing oral vaccines that are administered by tablet rather than by injection. Vaxart's programs are based on its proprietary oral vaccine platform called VAAST. The data came from Vaxart's 12-subject Phase 1b blinded study evaluating the ability of its norovirus vaccine to boost immunogenicity. Study participants were initially vaccinated with Vaxart's oral norovirus vaccine in late 2019 and were vaccinated again between February and April 2021. All seven participants who had been?previously immunized with the oral norovirus vaccine elicited?a?similar?broad range of?immune responses?to norovirus as the five subjects that had not received a prior oral vaccine dose.?? Key metrics identified in the boosting study were as follows: Serum antibody blocking titer 50,?a surrogate neutralizing antibody measurement, increased in both previously vaccinated and unvaccinated subjects by similar amounts. Antibody?secreting B cell (ASC) responses to norovirus VP1 measured?seven days post-boost were no different than?those in subjects receiving the vaccine for the first time. Serum IgG and IgA antibody responses were significantly elevated 29 days post-boost immunization, with no difference in titer between subjects that had received a prior oral norovirus vaccine?and those who had not previously been vaccinated.