Norovirus – also called the “winter vomiting bug” because it’s more common in winter – is a stomach bug that causes vomiting, diarrhoea and stomach cramps. Norovirus can be very unpleasant, but it usually clears up by itself within a few days, without treatment. It is also very contagious – a single person can easily infect the entire workplace, school or hospital ward. Most people get sick during the winter months, between January and March, and symptoms usually onset very fast. Worldwide, noroviruses are thought to be the most common cause of acute gastroenteritis (diarrhea and vomiting illness).


Noroviruses are members of a group of viruses called caliciviruses, that spreads rapidly through direct or indirect contact with infected persons. People acquire the virus by ingesting material contaminated with small amounts of infected feces or fluids. Food and water may be contaminated during processing or handling. 


According to the latest research, the virus can also be found in small, airborne water droplets, which increases further spread of infection.


The infection can be spread by:


  • direct contact with infected persons
  • drops in the air (for example, because of sneezing)
  • food touched by infected persons
  • contaminated water (not rinsed vegetables and berries)
  • raw seafood
  • contaminated clothes or toys.


The same person can suffer from norovirus several times, but others seem to have genetic traits that reduce the risk of disease.


Norovirus starts suddenly – the incubation period usually ranges from 12 to 48 hours. Typical symptoms include nausea and vomiting, diarrhea and abdominal pain. Many people also get muscle aches, headaches and fever. Vomiting is usually the most common symptom among children with norovirus, and adults are more often affected by diarrhea. Some can carry the virus without getting any symptoms at all.


In most cases, the problems usually pass within a few days, but pay attention to your general condition and signs of severe fluid deficiency. Children suffer more severely from dehydration than adults.


Bear in mind that nausea, diarrhea and abdominal pain do not necessarily mean you have norovirus. You may also be infected with a stomach flu caused by other viruses or food poisoning, which have similar symptoms. Sometimes, the problems may be caused by IBS or a peptic ulcer.

Prevention and protection

Vomiting and diarrhea can make the body very dehydrated, so getting enough fluid, in small amounts at frequent intervals, is important. 


When vomiting has stopped, you can start eating again. Small-size portions and bland food such as broth, soup, rice and white bread are easy to digest. Don’t consume milk products until the stomach has recovered.


If you are taking birth control pills, remember that severe diarrhea and vomiting can affect your contraceptive protection.


Although you typically feel better after a day or two, you’re contagious for a few days after you recover. The virus can remain in your stool for up to two weeks or more after recovery. Children should stay home from school or child care for at least 48 hours after the last time they vomit or have diarrhea. 


Do not touch foods that others might eat as long as you are infected. It is important to know that many can carry the virus without symptoms, so food and bathroom hygiene is very important. 


Some ways to reduce the risk of norovirus:


  • Always wash your hands with soap and use a paper towel to dry
  • Avoid contact with infected persons 
  • Avoid buffets where many people come in contact with the food
  • Boil frozen berries and vegetables
  • Wash textiles and toys before use – otherwise the virus can survive for a long time.


It is important to replace the fluid that the body loses, but as a rule, no other treatment is required. Norovirus often passes after one to three days. In some cases, if symptoms persist, it may be the sign of another disorder. In this case a medical investigation may be required.

When to consult a doctor

If you or your child have severe diarrhea or vomiting that does not go away, you should seek medical care. In case of severe abdominal pain, high fever or if you feel sick, tired and weak, you should contact a doctor. Serious symptoms of dehydration should also be followed up. If you have blood in the stool or bloody vomiting, you should seek urgent care. This also applies to severe stomach pains that do not go away, high fever and chills.

How APPOTEK can help

APPOTEK can help you with Norovirus. During the initial consultation, a nurse or doctor will make an individual assessment based on your symptoms. You may then be prescribed medicine or referred for further treatment. A physical examination is often required if an upset stomach is accompanied by abdominal pain. If your child has a problem, he or she may also need a physical examination.


Valeria Chernikova, Neurologist, M.D.