Cruise Ship Passengers Await Second-generation Oral Norovirus Vaccine Clinical Trial

With five norovirus outbreaks aboard cruise ships already reported by the U.S. CDC's Vessel Sanitation Program in 2025, there continues to be significant interest in accessing a preventive vaccine for this 'stomach virus.'

Over the past few years, viable norovirus vaccine candidates have been unsuccessful in preventing this highly contagious virus that causes acute gastroenteritis and can lead to substantial morbidity in older adults.

However, on March 5, 2025, Vaxart, Inc. announced that complete data from the Phase 1b trial of its first-generation oral pill norovirus vaccine candidate have been published in Science Translational Medicine. The data show strong and durable antibody responses and induction of norovirus-specific antibody and T cell responses.

“A key finding of this study evaluating our first-generation oral pill norovirus vaccine candidate in elderly individuals was that the antibody and serum responses observed in these participants were robust and durable, and a cross-study analysis suggested that the observed antibody and cellular responses were independent of age. These findings are encouraging given that older adults have an increased risk of norovirus-related morbidity and may have less robust immune responses following vaccination than younger individuals,” said James F. Cummings, MD, Chief Medical Officer at Vaxart, in a press release.

“Another key result was that an orally-administered vaccine can generate potent antibody responses in mucosal tissues outside the gastrointestinal tract, which could have important implications for use of our vaccine platform for norovirus and other indications.”

In January 2025, Vaxart announced that the next step in its norovirus program would be a Phase 1 clinical trial evaluating its second-generation oral norovirus vaccine constructs head-to-head against its first-generation constructs. This trial is expected to initiate in the first half of 2025.

While this is a good update, it means cruise ship passengers and crew may not have access to a norovirus vaccine this year.