When you fall ill

Winter vomiting disease - Calicivirus

Vinterkräksjuka - engelskaThe content concerns Jönköpings län

Winter vomiting disease is caused by the calicivirus and is one of the most common stomach bugs in Sweden. You can get an upset stomach for many different reasons. In order to prevent infection, good hygiene is essential, particularly washing your hands thoroughly with soap and water after you have been to the toilet.

Calicivirus affects all age groups. Children suffer most from vomiting, and adults from diarrhoea. Some people never get winter vomiting disease even if they have been exposed to the virus. This is probably due to a natural resistance.

Symptoms of winter vomiting disease

  • nausea
  • vomiting
  • diarrhoea
  • pain in the stomach

Symptoms can last for one to three days. You may also have:

  • fever
  • headache
  • muscle pain.

Problems tend to last one or two days, sometimes a day or so longer. You are usually no longer contagious two days after the symptoms have disappeared. Make sure that you are fully recovered before returning to work or school.

This illness is most common between November and April, with a peak between January and March. That is why it is called winter vomiting disease. But it can occur at other times of the year, when it is usually transmitted by contaminated food or water.

Winter vomiting disease can be similar to other stomach complaints, but differs from them in its sudden onset of symptoms.

How winter vomiting disease is transmitted

Winter vomiting disease is very contagious. A single person can infect an entire workplace or preschool. You can read more about how you can avoid becoming infected later in the text.

Winter vomiting disease is spread through:

  • direct contact with infected people
  • indirect contact with infected people; if someone vomits, the infection can be spread through tiny droplets in the air
  • food and drink that has been handled by someone who is ill or about to become ill
  • drinking water or food that has been washed in contaminated water and then not boiled, for example frozen berries and vegetables. Calicivirus is destroyed by temperatures in excess of 70 °C, but not by freezing
  • some shellfish that have been kept in water, for example oysters.

It normally takes between 12 and 48 hours from the time you are infected until you become ill.

If you have had winter vomiting disease, you may have a brief period of protection from the illness. You may, however, become sick several times.

When should I get treatment?

An upset stomach usually passes by itself after a few days. 

Contact your local health centre (vårdcentral) or call 1177 to get medical advice if:

  • you vomit a lot and are not getting enough fluids
  • you are urinating very little.

You should also contact a health centre or call 1177 if:

  • you are very tired and weak
  • you have bloody diarrhoea
  • you have a high fever and feel cold 
  • you have severe stomach pain or vomit repeatedly
  • you have a stomach problem and take medication for heart failure, diabetes or another serious condition
  • you work in the care or health profession or with food – you may need to take tests
  • your upset stomach occurred during or immediately after a trip abroad, especially if you have not had access to clean water
  • you have had diarrhoea for more than one week
  • the vomiting does not start to disappear within 24 hours.


The calicivirus is very contagious. Therefore always call the health centre before going there. The centre can then prepare for your visit and ensure that you do not infect anyone else. Here you can find contact info to your closest healthcare centre.

What can I do?

It is important to maintain the body’s fluid balance by drinking a lot. Your body absorbs fluid best if you drink little and often. If you find drinking difficult, you can take water by the teaspoonful. When you feel better, you can start eating again as normal, but should continue to take fluids frequently for as long as you have loose stools.

If you vomit a lot or have severe diarrhoea, the body loses both fluid and salts. You can then take rehydration solution to replace the water and the salts that your body has lost. You can buy rehydration solution at a pharmacy.

Avoid becoming infected

You can reduce the risk of becoming infected by:

  • always washing your hands thoroughly with soap and water, particularly before meals and after having been to the toilet. It is not enough to use hand sanitiser, as hand sanitiser does not affect the virus that causes winter vomiting disease
  • use liquid soap and paper towels in places where there are a lot of people, for example schools, preschools, workplaces and other public places
  • avoid eating from buffets where a lot of people come into contact with the food
  • avoid visiting people who have an upset stomach.

Avoid infecting others

You can reduce the risk of infecting others by:

  • washing your hands frequently with soap and water
  • not preparing food for other people
  • being extra careful with your personal hygiene
  • not going to places where you can infect others
  • staying home from school or other activities for at least 24 hours after any symptoms of vomiting and diarrhoea have cleared up.

You do not need to stay home from school if someone you live with is ill but you feel well. However, it is important to wash your hands thoroughly before leaving home and to go straight home if you develop symptoms.

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