Norovirus is a very contagious virus that can infect anyone. You can get it from an infected person, contaminated food or water, or by touching contaminated surfaces. The virus causes your stomach or intestines or both to get inflamed. This leads to stomach pain, nausea, diarrhea and vomiting.

Anyone can be infected with norovirus and get sick. Also, you can have norovirus illness many times in your life. Norovirus can be serious, especially for young children and older adults.

Norovirus is the most common cause of acute gastroenteritis in the United States. Each year, it causes 19-21 million illnesses and contributes to 56,000-71,000 hospitalizations and 570-800 deaths. Norovirus is also the most common cause of foodborne-disease outbreaks in the United States.

You may hear norovirus illness called "food poisoning" or "stomach flu". Food poisoning can be caused by noroviruses; however, other germs and chemicals can also cause food poisoning. Norovirus illness is not related to the flu (influenza), which is a respiratory illness caused by influenza virus.

What are the symptoms of norovirus?

Norovirus causes inflammation of the stomach or intestines or both, which is called acute gastroenteritis. The most common symptoms include diarrhea, vomiting, nausea and stomach pain. Other symptoms include fever, headache and body aches. Symptoms of norovirus can lead to dehydration. Symptoms of dehydration include decrease in urination, dry mouth and throat and feeling dizzy when standing up.

Most people with norovirus illness get better within 1 to 3 days.

How is norovirus spread?

Norovirus is spread by contaminated individuals touching items or handling food, or through vomit or feces of infected individuals. The illness is usually spread by:

• eating food or drinking liquids that are contaminated with norovirus,
• touching surfaces or objects contaminated with norovirus then putting your fingers in your mouth, or
• having contact with someone who is infected with norovirus (for example, caring for or sharing food or eating utensils with someone with norovirus illness).

Norovirus can spread quickly in closed places like daycare centers, nursing homes, schools and cruise ships. Most norovirus outbreaks happen from November to April in the United States.

What is the treatment for norovirus?

There is no specific drug to treat people with norovirus illness. There also is no vaccine to prevent norovirus infection. Norovirus cannot be treated with antibiotics because it is a viral (not bacterial) infection.

People with norovirus illness should drink plenty of liquids to replace fluid loss to help prevent dehydration. Dehydration can lead to serious problems, so it is important to contact a healthcare provider if you think you or someone you are caring for is severely dehydrated.

How can the spread of norovirus be prevented?

      Practice proper hand hygiene. Wash your hands carefully with soap and water, especially after using the toilet and changing diapers and always before eating, preparing or handling food.

      Wash fruits and vegetables and cook seafood thoroughly.

      When you are sick, do not prepare food or care for others who are sick. You should not prepare food for others or provide healthcare while you are sick and for at least 3 days after your symptoms stop. This also applies to sick workers in settings such as schools and daycares. 

      Clean and disinfected contaminated surfaces. After throwing up or having diarrhea, immediately clean and disinfect contamianted surfaces. Use a chlorine bleach solution with a concentration of 1000-5000 ppm (5-25 tablespoons of household bleach [5.25%] per gallon of water) or other disinfectant registered as effective against norovirus by the Environmental Protection Agency (EPA).

   Wash laundry thoroughly. Immediately remove and wash clothes or linens that may be contaminated with vomit or stool. You should:

• handle soiled items carefully without agitating them,
• wear rubber or disposable gloves while handling soiled items and wash your hands after, and
• wash the items with detergent at the maximum available cycle length then machine dry them.

For additional information on norovirus:

     Online Gastrointestinal (GI) Outbreak Reporting Form for Institutions

     Norovirus Fact Sheet (pdf)

     Norovirus in Health-Care Facilities (pdf)

     Norovirus Toolkit for Healthcare Settings (CDC)

     Guidelines for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings, 2011 (CDC) 

     Updated Norovirus Outbreak Management and Disease Prevention Guidelines (CDC MMWR, March 4, 2011 / 60(RR03);1-15)

     EPA's Registered Antimicrobial Products Effective Against Norovirus (pdf)