Norovirus activity remains elevated across several parts of the United States in early 2026, with public health monitoring showing increased outbreaks in schools, healthcare facilities, and cruise ships. Health officials say the rise generally matches the winter seasonal pattern for the virus, but some regions appear to be experiencing a higher level of transmission than in recent years.
A newer norovirus strain described as GII.17-like has become a major driver of outbreaks during the 2024–2025 and 2025–2026 seasons. Surveillance programs tracking viral samples have observed a shift away from the historically dominant GII.4 strains. Researchers believe lower population immunity to the newer variant, combined with ongoing viral evolution, may be helping sustain transmission and contribute to repeated outbreak waves.
Despite the emergence of new variants, public health guidance has not changed significantly. Officials continue to emphasize frequent handwashing with soap and water, disinfecting contaminated surfaces, and staying home while sick. People are also advised to avoid returning to work, school, or communal settings until at least 48 hours after symptoms stop, since the virus can continue spreading even after recovery begins. Experts say these basic prevention measures remain the most effective tools for limiting outbreaks.
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Weekly UKHSA report for the 2025/26 season, monitoring respiratory viruses.
www.gov.ukLower immunity to the new GII.17 strain could be leading to more infections.
www.cbsnews.comNorovirus, the highly contagious stomach bug that causes vomiting and diarrhea, is surging again. Here's what to expect and how to protect yourself.
www.today.comNorovirus, discovered in 1972, causes millions of gastroenteritis cases yearly. Learn prevention methods, symptoms, and updates on vaccine development.
www.infectioncontroltoday.comIdentify surveillance and reporting systems for norovirus and different roles in reporting.
www.cdc.govHuman Norovirus is currently the main viral cause of acute gastroenteritis (AGEs) in most countries worldwide. Nearly 50 years after the discovery of the “Norwalk virus” by Kapikian and colleagues, the scientific and medical community continue to ...
pmc.ncbi.nlm.nih.govSee number of suspected and confirmed norovirus outbreaks reported weekly by states in NoroSTAT.
www.cdc.govClinical Specimens … *71*). … Such information is critical to develop appropriate prevention and control strategies that target points of intervention most likely to yield the greatest impact. States are encouraged to contribute to this national surveillance effort by reporting all suspected and confirmed norovirus outbreaks through NORS.
www.cdc.govNoroviruses are nonenveloped, positive-sense, single-stranded RNA viruses belonging to the Caliciviridae viral family (see Image. Norovirus Virion). The virus was first identified and named “Norwalk virus” when it was discovered as the cause of a 1968 outbreak of gastroenteritis in Norwalk, Ohio. Norovirus is the leading cause of acute gastrointestinal illness worldwide. In developed countries with rotavirus vaccine programs, norovirus surpasses rotavirus as the most common cause of...
www.ncbi.nlm.nih.gov