Norovirus

Norovirus, sometimes known as the winter vomiting bug, is the most common stomach bug in the UK, affecting people of all ages.

Introduction

Norovirus, sometimes known as the winter vomiting bug, is the most common stomach bug in the UK, affecting people of all ages.

The virus, which is highly contagious, causes vomiting and diarrhoea. As there is no specific cure, you have to let it run its course, but it should not last more than a couple of days.

Read more about the symptoms of norovirus.

The period from when you are infected to when you start to show symptoms (known as the incubation period) usually lasts 12-48 hours. During this time, you may be infectious to other people.

Having norovirus can be an unpleasant experience, but it's not generally dangerous and most people make a full recovery within a couple of days, without having to see a doctor.

Noroviruses are a group of viruses that are the most common cause of stomach bugs (gastroenteritis) in the UK. They are also known as small round structured viruses (SRSV) or Norwalk-like viruses.

What should I do?

If you have norovirus, the following steps should help ease your symptoms:

  • Drink plenty of water to avoid dehydration.
  • Take paracetamol for any fever or aches and pains.
  • If you feel like eating, eat foods that are easy to digest.
  • Stay at home and don't go to the doctor, because norovirus is contagious and there is nothing the doctor can do while you have it.
  • However, contact your doctor to seek advice if your symptoms last longer than a few days or if you already have a serious illness.

Extra care should be taken to prevent babies and small children who are vomiting or have diarrhoea from dehydrating, by giving them plenty of fluids. Babies and young children can still drink milk.

Read more about treating norovirus.

Don't worry if you are pregnant and you get norovirus: there is no risk to your unborn child.

How to stop it spreading

The virus is easily spread by contact with an infected person, especially through their hands. You can also catch it through contaminated food or drink or by touching contaminated surfaces or objects.

The following measures should help prevent the virus from spreading further:

  • Wash your hands frequently.
  • Do not share towels and flannels.
  • Disinfect any surfaces that an infected person has touched.

Outbreaks in busy places such as hospitals, nursing homes and schools are common because the virus can survive for several days on surfaces or objects touched by an infected person.

If you have norovirus, you may continue to be infectious for a short period after symptoms stop, so you should avoid food preparation and direct contact with other people for at least 48 hours after your symptoms have gone.

Read more about preventing norovirus.

Symptoms

The first sign of norovirus is usually a sudden sick feeling followed by forceful vomiting and watery diarrhoea.

Some people may also have:

  • a raised temperature (over 38C/100.4F)
  • headaches
  • painful stomach cramps
  • aching limbs

Symptoms usually appear one to two days after you become infected but they can start sooner. Most people make a full recovery within a couple of days.

Apart from the risk of dehydration, the illness is not generally dangerous and there are usually no long-lasting effects from having norovirus. However, it can be pretty unpleasant while you have it.

Dehydration

The main risk from norovirus is dehydration from your body losing water and salts from vomiting and diarrhoea.

The first sign of dehydration is thirst. Other symptoms are:

  • dizziness or lightheadedness
  • headache
  • tiredness
  • dry mouth, lips and eyes
  • dark, concentrated urine
  • passing only small amounts of urine (fewer than three or four times a day)

Mild dehydration is common and can be easily reversed by making sure you have plenty to drink.

Dehydration is more of a risk in the very young and the elderly. It's important that you get medical attention straight away if you think your child is becoming dehydrated.

Severe dehydration

If you do not replace the lost fluid, dehydration will get worse and could lead to complications such as low blood pressure and kidney failure. It can even be fatal.

As well as severe thirst, you may also have:

  • dry, wrinkled skin
  • an inability to urinate
  • irritability
  • sunken eyes
  • a weak pulse
  • a rapid heartbeat
  • cold hands and feet
  • seizures

If you or your child have any symptoms of severe dehydration after catching a norovirus infection, seek medical attention as soon as possible.

Read more about treating norovirus.

Treatment

There is no specific treatment for norovirus.

It's best to let the illness run its course and your body usually fights off the infection within a couple of days. You don't need to see a doctor.

It is important to have plenty to drink and, if you feel the need, paracetamol for any fever or aches and pains.

Try to eat foods that are easy to digest, such as soup, rice, pasta and bread. Babies should continue with their normal feeds.

To reduce the risk of passing the virus on to others, wash your hands regularly and stay at home until you are clear of symptoms for 48 hours.

Avoid dehydration

Drinking plenty of fluids is particularly important for young children and the elderly, as they are more prone to dehydration. They will need urgent medical treatment if they start to show signs of dehydration.

A healthy adult should drink about 1.2 litres (six to eight glasses) of fluid every day to stop getting dehydrated. Someone with norovirus will need to drink more than that to replace the fluids lost from vomiting and diarrhoea.

Suitable drinks include water, squashes and fruit juice. If you are finding it hard to keep down fluids, try to take small sips more frequently to keep yourself hydrated.

Infants and small children should receive frequent sips of water even if they vomit. A small amount of fluid is better than none. Avoid giving fruit juices and carbonated drinks to children under the age of five, as these can worsen diarrhoea.

Read more about treating babies and [children with diarrhoea or who are vomiting].

Rehydration drinks

If you are worried that you are becoming dehydrated, your doctor or pharmacist may advise you to take rehydration drinks.

You can buy sachets of rehydration salts from your pharmacy and add them to water. They provide the correct balance of water, salt and sugar for your body.

Not all rehydration drinks are suitable for children. You should check which ones are suitable with your doctor or pharmacist. Read more information about treating dehydration.

If your symptoms continue for more than three days or you feel severely dehydrated at any time, get medical help immediately.

Advice for parents

Keep your child away from school or nursery for at least 48 hours after their last episode of diarrhoea or vomiting.

Also, children should not swim in a swimming pool for two weeks following the last episode of diarrhoea.

Read more about preventing norovirus.

Prevention

Getting norovirus cannot always be avoided, but good hygiene can help to limit the virus spreading.

Tips to help stop the virus spreading:

  • Wash your hands frequently and thoroughly with soap and water, particularly after using the toilet and before preparing food.
  • Do not share towels and flannels.
  • Disinfect any surfaces or objects that could be contaminated with the virus. It is best to use a bleach-based household cleaner.
  • Wash any clothing or bedding that could have become contaminated with the virus. Wash the items separately and on a hot wash to ensure that the virus is killed.
  • Flush away any infected faeces or vomit in the toilet and clean the surrounding toilet area.
  • Avoid eating raw, unwashed produce and only eat oysters from a reliable source. Oysters have been known to carry the norovirus.

If you have norovirus, avoid direct contact with other people, and preparing food for others, until at least 48 hours after your symptoms have gone. You may still be contagious, even though you no longer have sickness or diarrhoea.

Avoid visiting hospitals if you have had the typical symptoms of norovirus in the past 48 hours. Some hospitals may request you avoid visiting if you have experienced symptoms within the past 72 hours. Norovirus is more serious and even more easily spread among people who are already ill.

You may be asked to rearrange a medical appointment if you have had recent symptoms.

Content supplied by NHS Choices