Norovirus Vaccines

Norovirus Vaccine Candidate October 2025

While vaccines against Human norovirus (HuNoVs) disease are in demand, developing a broadly effective vaccine remains challenging in 2025, owing to the vast genetic and antigenic diversity of noroviruses, which have multiple co-circulating variants of different genotypes. As of October 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

JAMA published a news article on a norovirus vaccine on July 25, 2025, summarizing current development efforts.

Research Article published in March 2025; Broadly neutralizing antibodies targeting pandemic GII.4 variants or seven GII genotypes of human norovirus demonstrate that norovirus human monoclonal antibodies with broad GII.4 potency and cross-GII breadth can be boosted in serum after immunization with an adenoviral vector–based vaccine, findings that may guide the design of immunogens for broadly protective norovirus vaccines.

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 in 2025. In May 2025, a phase 2b randomized, placebo-controlled vaccination and challenge study to assess the safety, efficacy, immunogenicity, and correlates of protection of VXA-G1.1-NN, an oral tablet norovirus vaccine. VXA-G1.1-NN was found to be safe and well-tolerated, conferred protection against norovirus GI.1 challenge, and reduced viral shedding in stool and emesis. The vaccine candidate was immunogenic and protected against norovirus infection, with a 30% relative reduction in the vaccine group compared with the placebo group (p = 0.003).

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.

HilleVax 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. Food and Drug Administration (FDA) cleared an Investigational New Drug application for HIL-216 in September 2023. Vaccine development was discontinued in 2024.

Anhui Zhifei Longcom Biologic Pharmacy Co., Ltd. is conducting a Phase 1/2a clinical trial to evaluate the safety and tolerability of a tetravalent recombinant Norovirus vaccine at various doses. This candidate utilizes the Pichia pastoris expression system, which enables the production of virus-like particles (VLPs) recombinant engineered bacteria for expressing norovirus epidemic strains, which are then cultured.

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

Norovirus Treatment 2025

Cocrystal Pharma, Inc. announced on January 8, 2025, favorable safety and tolerability results at doses of up to 800 mg per day for 10 consecutive days from the multiple-ascending dose portion of its 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 national trends for Norovirus. Approximately 2,500 reported norovirus outbreaks occur in the United States each year. In 2019, norovirus infections resulted in approximately 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. Eighteen potential norovirus outbreaks were reported in 2025; 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.