What is the norovirus?
About 1 in every 15 people in the US will get the norovirus annually which causes approximately 109,000 hospitalizations and 2.3 million outpatient visits. The norovirus is one of the most common causes of gastroenteritis which is an inflammation in the stomach or intestines. It is the leading cause of vomit, diarrhea, and foodborne illnesses in the United States. Outbreaks of the norovirus usually happen in the winter season. During August 1 to December 11, 2024, there were 495 norovirus outbreaks in the US. In total, the number of outbreaks in the 2024 to 2025 season reported a higher threshold than the previous years.
Who can get infected with the norovirus?
People of all ages can get the norovirus, but younger children, older adults, and those with weakened immune systems are at higher risk of infection.
How does the norovirus spread?
The norovirus spreads through contaminated food, surfaces, or direct contact with infected individuals. The virus is prominent in foods such as raw or undercooked shellfish that will increase the risks of infection.
What are the symptoms of the norovirus?
Symptoms of the norovirus typically develop 12 to 48 hours after the exposure and can even last from 1 to 3 days. Some of the common symptoms are diarrhea, vomiting, nausea, stomach pain, fever, headache, and body aches. Severe vomiting and diarrhea can also lead to dehydration. Some signs of dehydration can present as decreased urination, dry mouth, dizziness, and unusual sleepiness. That is why adequate hydration is crucial for recovery.
How can I prevent norovirus infection?
There are different techniques to use against the norovirus. The most common ones are handwashing, preparation of food and safety, and cleaning. It is important to maintain good hygiene to prevent the norovirus from spreading.
- Handwashing: Make sure you wash your hands with soap and water for at least 20 seconds especially after using the toilet, changing diapers, or handling food. The use of hand sanitizer alone is not effective against norovirus, but it can be used in addition to handwashing.
- Avoid preparing for food when you are sick: Do not prepare food while sick for at least 48 hours after the symptoms stop. This is crucial for settings such as restaurants, schools, and healthcare facilities to prevent the virus from spreading.
- Food: When cooking shellfish, make sure it is adequately cooked to a minimum temperature of 145oF. And make sure raw oysters are separated from your cooked foods to avoid cross-contamination. Always wash fruits and vegetables before eating. It is also important to wash and sanitize all kitchen utensils, cutting boards, and surfaces after every use. In addition, make sure to discard any food that looks, smells, or tastes abnormal.
- Cleaning: It is important to maintain proper hygiene at all times to prevent the virus from spreading. Always wear gloves when cleaning and use disposable paper towels when cleaning. The CDC recommends disinfectant with a bleach solution (1,000-5,000 ppm or 5-25 tablespoons bleach per gallon of water) or an EPA-registered disinfectant. Additionally, make sure that you allow the disinfectant to sit for at least 5 minutes before cleaning the area again with soap and hot water. For laundry that is contaminated with vomit or feces, it is important to remove and wash linen and clothing with hot water and detergent on the longest available cycle and dry on the highest heat setting. Most importantly, make sure you wash your hands thoroughly after cleaning.
Is there a treatment for norovirus?
There is not a cure for the norovirus, but there are treatments that can help with symptom relief. Be sure to drink plenty of fluids with electrolytes, get a lot of rest, and eat soft/bland foods.
When should I seek medical attention?
Signs of severe dehydration are dizziness, confusion, fainting, unusual sleepiness, vomit and lethargy. If you are experiencing any of these symptoms from the norovirus, seek medical attention.
Written by:
Kevin Lin
PharmD Candidate 2025
Philadelphia College of Pharmacy
References
About norovirus [Internet]. Centers for Disease Control and Prevention; [cited 2025 Jan 17]. Available from: https://www.cdc.gov/norovirus/about/index.html
How to prevent norovirus [Internet]. Centers for Disease Control and Prevention; [cited 2025 Jan 17]. Available from: https://www.cdc.gov/norovirus/prevention/index.html
Norostat Data [Internet]. Centers for Disease Control and Prevention; [cited 2025 Jan 17]. Available from: https://www.cdc.gov/norovirus/php/reporting/norostat-data.
Norovirus: It isn’t the stomach flu [Internet]. 2025 [cited 2025 Jan 17]. Available from: https://my.clevelandclinic.org/health/diseases/17703-norovirus