An oral norovirus vaccine generates mucosal immunity and reduces viral shedding in a phase 2 placebo-controlled challenge study.

There are currently no licensed vaccines for norovirus, a leading cause of epidemic and endemic gastroenteritis worldwide. Clinical advancement of promising vaccine candidates from phase 2 studies to phase 3 field trials has been hampered by the lack of robust immunological correlates of protection. Here, we conducted a phase 2b randomized, placebo-controlled vaccination and challenge study to assess the safety, efficacy, immunogenicity, and correlates of protection of VXA-G1.