Norovirus Vaccines

Norovirus Vaccine Candidate Clinical Trials

While vaccines against Human noroviruses (HuNoVs) disease are in demand, developing a broadly effective vaccine in 2025 remains challenging owing to the vast genetic and antigenic diversity of noroviruses, which have multiple co-circulated variants of different genotypes. As of March 24, 2025, the U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA), and the U.K. had not approved a norovirus vaccine, and the World Health Organization (WHO) has not pre-qualified any norovirus vaccine.

Norovirus Vaccine Candidates 2025

Moderna Inc. is developing two multivalent virus-like particle vaccines, mRNA-1403 (trivalent) and mRNA-1405 (pentavalent), to prevent norovirus infections. The Nova 301 Phase 3 trial is a randomized, observer-blind, placebo-controlled trial evaluating the efficacy, safety, and immunogenicity of mRNA-1403. In 2025, Moderna announced the US FDA placed a clinical hold following a single adverse event report of a case of Guillain-Barré syndrome, which is currently under investigation. The Company does not expect an impact on the study's efficacy readout timeline, as enrollment in the Northern Hemisphere has already been completed. The timing of the Phase 3 readout will be dependent on case accruals.

HIL-214 was a bivalent vaccine candidate in development for preventing moderate-to-severe acute gastroenteritis. HilleVax's HIL-216 hexavalent virus-like particle (VLP) vaccine candidate for norovirus includes VLPs for six of the most common norovirus genotypes, including GI.1, GII.2, GII.3, GII.4, GII.6, and GII.17. The U.S. FDA cleared an Investigational New Drug application for HIL-216 in September 2023.

Vaxart Inc.'s orally administered bivalent GI.1/GII.4 norovirus oral vaccine candidate showed robust, antigen-specific responses in the nasal cavity following oral administration in a phase 1b study. If the new Phase 1 trial succeeds, and assuming a partnership or other funding, Vaxart expects to conduct a Phase 2 safety and immunogenicity study that could begin as early as the second half of 2025.

Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd. is conducting a phase 1/2a clinical trial evaluating the safety and tolerability of the tetravalent recombinant Norovirus vaccine at different doses. This candidate uses the Pichia pastoris expression system, which establishes the virus-like particles (VLP) recombinant engineered bacteria for expressing norovirus epidemic strains, which are then cult.

Cocrystal Pharma, Inc. oral, first-in-class pan-norovirus and pan-coronavirus 3CL protease inhibitor CDI-988 dosed the first subjects in a Phase 1 clinical trial on September 29, 2023. Recent CDI-988 in vitro studies showed potent broad-spectrum antiviral activity against a panel of pandemic GII.4 norovirus proteases and a favorable pharmacokinetic property targeting the gastrointestinal tract. 

Norovirus Treatment 2025

Cocrystal Pharma, Inc. announced on January 8, 2025, favorable safety and tolerability results at doses up to 800 mg per day for 10 consecutive days from the multiple-ascending dose portion of the ongoing Phase 1 study with its oral protease inhibitor CDI-988. CDI-988 is the first pan-viral drug candidate in development for the orally administered treatment of norovirus and coronavirus infections. 

Travelan® is an orally administered passive immunotherapy that prophylactically reduces the likelihood of contracting travelers' diarrhea. In Australia, Travelan® is a listed medicine on the Australian Register for Therapeutic Goods. It is antimicrobial and indicated to reduce the risk of Travelers' Diarrhea and minor gastrointestinal disorders. In Canada, Travelan® is a licensed natural health product that reduces the risk of Travelers' Diarrhea. In the U.S., Travelan® is sold as a dietary supplement for digestive tract protection.

Norovirus Outbreaks

Based on CaliciNet Data, the U.S. Centers for Disease Control and Prevention CDC published the Norovirus Outbreak Map in 2025. The Wastewater SCAN Norovirus map is updated in 2025. The CDC also posts Norovirus National Trends. The CDC says the GII.4 proteases have caused most norovirus outbreaks since 2024; however, non-GII.Four viruses, such as GII.17 and GII.2, have replaced GII.4 viruses in several Asian countries. Separately, the U.K. Health Security Agency publishes summaries of norovirus and rotavirus laboratory surveillance and enteric virus outbreaks in hospital and community settings in England during the 2022 to 2023 season.

Each year, about 2,500 reported norovirus outbreaks occur in the United States. In 2019, norovirus infections caused about 5.5 million illnesses and 22,400 hospitalizations.

Norovirus Cruise Ship Outbreaks

The U.S. CDC and the U.K. identified norovirus outbreaks and issued ts for the cruise ship industry in 2025. Ten norovirus outbreaks were reported in 2025, and twelve occurred on cruise ships in 2024 and 2023. A University of Surrey–led research team identified cruise ship dining areas as priorities for preventing disease outbreaks.