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If you’ve ever been sick with norovirus, you probably remember it. It’s a virus that is one of the top causes of the stomach flu (acute gastroenteritis), sometimes called the stomach bug.

Symptoms of gastroenteritis include nausea or vomiting, diarrhea and stomach cramping or pain. Some people also have a low fever, headache and body aches. Symptoms usually start 12 to 48 hours after exposure to the virus and last for one to three days.

Norovirus is very contagious. It can quickly spread through families and people who work or go to school together. 

Even though people call gastroenteritis the stomach flu, it’s not actually caused by the influenza virus. So your annual flu shot will not protect you against the stomach flu, but it will give you protection against flu viruses that cause respiratory (breathing) infections.

How norovirus spreads

There are a few ways you can catch norovirus. You can come in contact with someone who’s infected, touch a surface that has the virus on it or eat or drink contaminated food or water. In fact, norovirus is one of the top causes of food poisoning.

If you’re infected with norovirus, you’re contagious from the moment symptoms start until a few days after they end. Since norovirus is so contagious, you should stay home from work, school and public places during this time. 

Norovirus outbreaks can happen anywhere people are close to each other, such as schools and daycares, health care facilities, community events or cruise ships. Norovirus can also spread at restaurants if anyone preparing food is infected.

Outbreaks can happen any time of year. In the United States, they are most common from November through April.

Here are some tips to avoid norovirus:

  • Alcohol-based hand sanitizers may not work against norovirus, so wash your hands with soap and water several times a day. Be sure to wash your hands after you use the bathroom or change diapers, after you cough or sneeze and before you handle food or give someone medicine.
  • Avoid sharing personal items such as forks, spoons, cups and toothbrushes.
  • Try not to touch your face or mouth since it’s easy for germs to move from your hands into your body this way.
  • Regularly disinfect surfaces and objects that people touch a lot, such as doorknobs, handles, remote controls and light switches.
  • Clean and sanitize kitchen counters and surfaces.
  • Wash fruits and vegetables.
  • Cook all meats and seafood until they are at a safe temperature

How to treat norovirus

There’s no antiviral treatment you can take for norovirus. Most people get better on their own in one to three days. However, here are some things you can do to keep your symptoms under control:

  • Drink plenty of fluids: You may not feel like drinking anything, but vomiting and diarrhea can cause dehydration. Water, clear broths and electrolyte drinks can help you replace lost fluids. Drink small sips often to lessen the likelihood of vomiting. 
  • Rest: Rest allows your body to use its energy to fight the virus, so you’ll heal faster. 
  • Consider OTC medications: Over-the-counter (OTC) medications like Kaopectate and Imodium A-D can treat diarrhea. Be sure to talk to a pharmacist or your health care provider before treating diarrhea with medication. This is very important if you are treating children, seniors or people who have other health conditions. In general, anti-diarrheal medication use is discourage in children unless instructed by their doctor or health care provider.
  • Avoid solid foods: You can try natural remedies for an upset stomach. It’s best to stick with liquids until vomiting and diarrhea stop. After that, eating bland, easy-to-digest foods like bananas, rice, applesauce, plain toast, oatmeal and crackers can help.
  • Steer clear of dairy foods for 48 hours: To avoid more diarrhea, your digestive system needs to heal for a couple days before you eat dairy.

For most people, norovirus passes in a few days. The biggest risk when you have norovirus is dehydration. If you are dehydrated, you may notice that you have a dry mouth or throat, you aren’t urinating as often or as usual (or your urine is dark yellow) and you get dizzy when you stand up. 

Children, seniors and people who have weakened immune systems are at higher risk of dehydration. Signs of concern for infants include excessive sleepiness, excessive irritability, a decreased number of web diapers, a lack of tears or a dry or sticky mouth.

Be sure to call your health care provider if you think you may be dehydrated, your symptoms get worse or last more than a few days, vomiting doesn’t stop or you have blood in your stool (or bloody diarrhea).

How to keep norovirus from spreading

If someone in your household is infected with norovirus, someone else can easily get sick by being exposed to the virus. 

These steps can help keep others from being infected:

  • Be sure the sick person stays home and in their own room. Once they are feeling better, they should stay there for two more days after symptoms end.
    • Contact your child’s school for guidance on when it is okay to return. Many schools restrict attendance until at least 48 hours after vomiting and loose stools have gone away. 
  • Bleach is more effective at killing norovirus than most disposable household cleaning wipes.
    • Wipe high-traffic surfaces like doorknobs, light switches and tables with a spray made of five to 25 tablespoons of bleach mixed with a gallon of water.
    • You may want to test this solution on a non-noticeable spot first to make sure it doesn’t discolor the surface.
    • Let the spray sit for five minutes, then wipe it up.
    • Keep in mind that the norovirus can become airborne when someone vomits, and these airborne particles can contaminate close-by surfaces. Be sure to clean these areas as well.
  • Wash dirty clothes and sheets in hot water with detergent for the longest cycle time. Dry them in the dryer on the highest setting.
  • Wear disposable gloves and a mask when cleaning or doing laundry and throw them away when you’re done.
  • Use disposable towels when cleaning surfaces that have vomit or diarrhea on them. Throw them away immediately in a plastic bag. 
  • If in doubt, throw away suspicious food - especially if a sick person touched it or if you think it could be contaminated with the virus. 
  • Don’t allow the sick person to prepare food for others for at least two days after symptoms end to avoid contaminated food.

Norovirus key points

A norovirus infection can cause viral gastroenteritis and symptoms like vomiting and diarrhea. Most people recover at home in a few days, but it can cause severe dehydration in some people, especially infants and young children, seniors and people with other health conditions. 

Norovirus is highly contagious, so it’s important to take steps to avoid infection. You should wash your hands often - especially before you handle food - and stay home if you’re sick.