Norovirus: What You Need to Know

Introduction

More than just the typical respiratory viruses are circulating this season. Each year between November and December, norovirus, also called the stomach flu, surges in the United States (US).^1–5 At the end of December 2025, the US Centers for Disease Control and Prevention (CDC) reported a national positivity rate of 14.1%.⁶ Although this wave of the winter vomiting bug is not unexpected, especially after last year’s record-breaking season, this trend has health experts worried. This wave arrived weeks ahead of the CDC’s predictions, and a new ultra-contagious strain, subvariant GII.17, has entered the scene.^1,7,8 As the usual bouts of seasonal illness continue to swirl this winter, here’s what you need to know to protect yourself from norovirus. 

What Is Norovirus?

Norovirus is a group of viruses belonging to the Caliciviridae family.^9–11 When the virus enters the body, the stomach and intestines swell and become inflamed, a condition called gastroenteritis. This leads to the trademark symptoms of norovirus, severe vomiting and diarrhea.^6,9–13 This illness is fairly common; about 1 in every 15 people in the US is infected annually, and the CDC records roughly 2,500 norovirus outbreaks each year. It is also the leading cause of foodborne illness, responsible for nearly 58% of cases in the US.^2,12–14

Norovirus is highly contagious. Anyone, at any age, is susceptible to contracting the virus, which spreads through close contact or via contaminated food or surfaces.^6,9–12 People infected with it shed billions of tiny virus particles in their feces and vomit that can make others sick. It only takes a few particles to make someone else ill, and these germs can linger on surfaces for several days or weeks. People can also be contagious for up to 2 weeks after symptoms disappear.^12,15 

All of these factors make certain settings and populations more susceptible to norovirus. People living or working in semi-enclosed or enclosed spaces, such as schools, long-term care facilities, prisons, and college dormitories, are more likely to contract the virus. The same is true for those on cruise ships.⁴ This is also what makes certain age groups more vulnerable.⁶ Children between 6 and 18 months are a high-risk group because they spend time in daycare, a close-quarters setting that poses hygiene challenges and involves sharing items, such as toys. Seniors, especially those living in assisted living spaces or nursing homes, face similar challenges.¹⁶ People who are immunocompromised are another vulnerable group.

Signs, Symptoms, and Treatment

Once a person comes into contact with norovirus, it takes 12 to 48 hours to start exhibiting symptoms, the onset of which are usually sudden and harsh.¹¹ The most common symptoms are diarrhea, vomiting, nausea, and stomach pain, but some people might also develop a fever, headache, and body aches.^4,9,12,13,16 Diagnosis is often based on the presence of these symptoms. Testing usually isn’t necessary, but a provider may test a stool sample to confirm the diagnosis. There is no medicine or targeted therapy for norovirus; antibiotics are not effective against viral infections. Treatment focuses on symptom management while letting the illness run its course.^3,4,9,12,17 Most people will recover on their own within 3 days.

The symptoms of norovirus often introduce a more subtle risk: dehydration. This can turn a short-term bout of illness into a medical emergency, especially in young children and the elderly. Although deaths are rare, norovirus kills about 900 Americans every year, and these populations are particularly vulnerable.^11,12 The condition has also led to more than 100,000 hospitalizations and 465,000 emergency department visits annually.¹² Even though the thought of eating or drinking can be nauseating, experts suggest sipping water, an oral hydration solution, or electrolyte drinks throughout the day to prevent dehydration and stave off emergency visits and care.¹²

Prevention

Norovirus is a highly contagious and resilient virus, but there are a few prevention strategies that can mitigate its spread. Whether you’re sick or you’ve been exposed to the infection, consider the following advice.

Wash your hands. Thoroughly wash your hands with soap and warm water for at least 20 seconds, especially after using the bathroom or coming into contact with contaminated surfaces. Unlike many other illnesses, hand sanitizer is not 100% effective against norovirus.^6,11,18 A combination of both works best.

Disinfect surfaces. Norovirus is also resistant to most disinfectants. The US Environmental Protection Agency has a list of disinfectants effective against norovirus, but you can create your own cleaner at home.¹⁹ The CDC recommends creating a chlorine bleach solution using 5 to 25 tablespoons of household bleach (5–8%) per gallon of water, leaving it on the affected surface for at least 5 minutes, and cleaning the entire area again with soap and hot water.¹⁹

Clean up carefully. Using disposable gloves, clean up vomit and stool with disposable towels. Then seal them in a plastic bag and dispose of them in the trash. Even on soft surfaces, like carpets, linens, and fabrics, norovirus can be viable for a few days to a week.²⁰ Launder any soiled items with detergent and hot water at the maximum available cycle length and machine dry them at the highest heat setting.^17,18

Handle and prepare food safely. Most reported norovirus outbreaks are caused by people who are sick and touch or prepare food. If you are exposed to norovirus or become ill, avoid cooking areas and do not prepare, handle, or serve food. Infected people should abstain from these activities and spaces for at least 48 hours after their symptoms stop.²¹ In addition to proper handwashing, all people should carefully wash fruit and vegetables before cooking or eating them. Noroviruses are relatively heat-resistant and can survive temperatures up to 145 °F.^12,15,18,22 This is one of the reasons why filter-feeding shellfish like oysters, which are often eaten raw, are one of the foods most commonly involved in norovirus outbreaks.^12,21,22

Stay home and isolate. One of the most effective strategies for staving off norovirus is the standard public health prevention advice: staying home when sick. People who have been exposed to norovirus should stay home for at least 48 hours, the maximum incubation period, because you can be infectious before symptoms appear.²⁰ Those who do become sick should do their best to self-isolate in their home, ideally in a space with its own bathroom, and wait until they’ve been symptom-free for 2 days before returning to their normal routine.

A Vaccine on the Horizon

Even though norovirus was first identified more than 50 years ago and has a significant economic burden, there are no approved vaccines or antiviral treatments for this common illness.^{4,5,11,14,23–25} This is because the virus is a master adapter. Like influenza viruses, norovirus undergoes continuous genetic shifts, and our immune system can struggle to recognize and respond when we’re exposed to it, even if we’ve had it before.^23,26 There are at least 49 different norovirus genotypes, and growing these cells in a lab has proven difficult.^27–29 These 3 factors—norovirus’s evolution, genetic diversity, and troublesome cell-culture processes—make the body’s immune response complex and the virus difficult to study, posing challenges for vaccine design.^4,23,26–30 

Progress in norovirus vaccinology has accelerated over the past couple of decades, and there have been a few recent developments.^23,28 Several novel approaches and vaccine types have been tested, but all have progressed in fits and starts.³⁰ Even though a norovirus vaccine is still years away—some experts estimate that the earliest possible approval will happen in the next 3 to 5 years—the research community seems hopeful and the science promising.^1,23,28–31

Sources

1. Scribner H. What to know about the surging “winter vomiting bug” and Its contagious new variant. Axios. 23 Dec 2025. Accessed 17 Jan 2026. https://www.axios.com/2025/12/24/norovirus-winter-vomiting-bug-variant-symptoms
2. Scribner H. This highly contagious “winter vomiting disease” is surging across the country. Axios. 2 Dec 2025. Accessed 17 Jan 2026. https://www.axios.com/2025/12/03/norovirus-winter-vomiting-disease-bug-symptoms
3. Bajaj S. What to know about norovirus. New York Times. 22 Dec 2025. Accessed 5 Jan 2026. https://www.nytimes.com/2025/12/22/well/norovirus-symptoms-precautions.html 
4. Schaffner W. Norovirus, aka the winter vomiting bug, is on the rise – an infectious disease expert explains the best ways to stay safe. The Conversation. 27 Jan 2025. Accessed 5 Jan 2026. https://theconversation.com/norovirus-aka-the-winter-vomiting-bug-is-on-the-rise-an-infectious-disease-expert-explains-the-best-ways-to-stay-safe-247667
5. NoroSTAT data table. US Centers for Disease Control and Prevention. Updated 17 Dec 2025. Accessed 5 Jan 2026. https://www.cdc.gov/norovirus/php/reporting/norostat-data-table.html
6. Berg S. What doctors wish patients knew about the contagious norovirus. American Medical Association. 24 Jan 2025. Accessed 5 Jan 2026. https://www.ama-assn.org/public-health/infectious-diseases/what-doctors-wish-patients-knew-about-contagious-norovirus
7. The National Respiratory and Enteric Virus Surveillance System (NREVSS) Dashboard. US Centers for Disease Control and Prevention. Updated 18 Jun 2025. Accessed 17 Jan 2026. https://www.cdc.gov/nrevss/php/dashboard/index.html
8. Tin A. Will norovirus surge early again this year? CDC urges tracking of new strain. CBS News. Updated 14 Jan 2025. Accessed 17 Jan 2026. https://www.cbsnews.com/news/norovirus-surge-early-cdc-tracking-new-strain/
9. Norovirus. Cleveland Clinic. Updated 2 Feb 2023. Accessed 5 Jan 2026. https://my.clevelandclinic.org/health/diseases/17703-norovirus
10. Capece G, Tobin EH. Norovirus.  In: StatPearls. Treasure Island (FL): StatPearls Publishing; Updated 17 Feb 2025. Accessed 22 Jan 2026. https://www.ncbi.nlm.nih.gov/books/NBK513265/ 
11. Robilotti E, Deresinski S, Pinsky BA. Norovirus. Clin Microbiol Rev. 2015;28(1):134–164.
12. About norovirus. US Centers for Disease Control and Prevention. 24 Apr 2024. Accessed 5 Jan 2026. https://www.cdc.gov/norovirus/about/index.html
13. Norovirus. National Foundation for Infectious Diseases. Updated Jan 2026. Accessed 5 Jan 2026. https://www.nfid.org/infectious-disease/norovirus/
14. Norovirus facts and stats. US Centers for Disease Control and Prevention. 8 May 2024. Accessed 5 Jan 2026. https://www.cdc.gov/norovirus/data-research/index.html
15. How norovirus spreads. US Centers for Disease Control and Prevention. Updated 24 Apr 2024. Accessed 5 Jan 2026. https://www.cdc.gov/norovirus/causes/index.html
16. Tsai H, Yune P, Rao M. Norovirus disease among older adults. Ther Adv Infect Dis. 2022;9:20499361221136760.
17. Mayo Clinic Staff. Norovirus infection. The Mayo Clinic. 30 Apr 2025. Accessed 5 Jan 2026. https://www.mayoclinic.org/diseases-conditions/norovirus/symptoms-causes/syc-20355296
18. How to prevent norovirus. US Centers for Disease Control and Prevention. Updated 13 Jan 2025. Accessed 5 Jan 2026. https://www.cdc.gov/norovirus/prevention/index.html
19. EPA’s registered antimicrobial products effective against norovirus (feline calicivirus) [list G]. US Environmental Protection Agency. Updated 15 Oct 2025. Accessed 18 Jan 2026. https://www.epa.gov/pesticide-registration/epas-registered-antimicrobial-products-effective-against-norovirus-feline
20. Norovirus germs can live on surfaces for up to two weeks. Cleveland Clinic. 11 Mar 2025. Accessed 18 Jan 2026. https://health.clevelandclinic.org/how-long-do-norovirus-germs-live-on-household-and-office-surfaces
21. Norovirus fact sheet for food workers. US Centers for Disease Control and Prevention. Updated 8 May 2024. Accessed 18 Jan 2026. https://www.cdc.gov/norovirus/communication-resources/facts-for-food-workers.html
22. Norovirus outbreaks. US Centers for Disease Control and Prevention. 24 Jul 2025. Accessed 5 Jan 2026. https://www.cdc.gov/norovirus/outbreak-basics/index.html
23. Hansman G. Could we one day get vaccinated against the gastro bug norovirus? Here’s where scientists are at. The Conversation. 5 Aug 2025. Accessed 5 Jan 2026. https://theconversation.com/could-we-one-day-get-vaccinated-against-the-gastro-bug-norovirus-heres-where-scientists-are-at-258909
24. Bartsch SM, Lopman BA, Ozawa S, et al. Global economic burden of norovirus gastroenteritis. PLoS One. 2016;11(4):e0151219.
25. Kapikian AZ, Wyatt RG, Dolin R,et al. Visualization by immune electron microscopy of a 27-nm particle associated with acute infectious nonbacterial gastroenteritis. J Virol. 1972;10(5):1075–1081.
26. Singh BK, Leuthold MM, Hansman GS. Human noroviruses’ fondness for histo-blood group antigens. J Virol. 2015;89(4):2024–2040.
27. Chhabra P, de Graaf M, Parra GI, et al. Updated classification of norovirus genogroups and genotypes. J Gen Virol. 2019;100(10):1393–1406.
28. Tan M. Norovirus vaccines: current clinical development and challenges. pathogens. 2021;10(12):1641.
29. Hayashi T, Kobayashi S, Hirano J, Murakami K. Human norovirus cultivation systems and their use in antiviral research. J Virol. 2024;98:e0166323.
30. Schweitzer K. Is there a norovirus vaccine on the horizon? JAMA. 2025;334(8):656–658.
31. Geddes L. Vomit-proof: how close are we to a norovirus vaccine? Gavi. 2 Jun 2025. Accessed 18 Jan 2026. https://www.gavi.org/vaccineswork/vomit-proof-how-close-are-we-norovirus-vaccine