Norovirus (vomiting bug)
Norovirus is the commonest cause of that sudden vomiting-and-diarrhoea illness which shuts nursery rooms and whole hospital wards.
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Norovirus is the commonest cause of that sudden vomiting-and-diarrhoea illness which shuts nursery rooms and whole hospital wards. The nickname "winter vomiting bug" has stuck because outbreaks cluster in the cold months, but the virus has nothing to do with flu and can be caught at any time of year. The illness is short and in the great majority of cases clears up on its own within a couple of days. What is dangerous is not the virus itself but the loss of fluid — particularly in babies, older people and anyone already unwell. So everything worth knowing about norovirus comes down to two things: how to stop yourself becoming dehydrated, and how to avoid passing it on.
How the illness runs
Between catching it and the first symptoms, twelve to forty-eight hours go by. The start is usually abrupt and without warning: a person feels sick and minutes later is vomiting. Watery diarrhoea follows, with no blood or mucus in it.
Along with that there may be:
- cramping tummy pain and rumbling;
- a raised temperature, usually not a high one;
- headache and aching muscles;
- a flattened feeling that makes getting up seem impossible.
The worst falls on the first day; then the vomiting settles and the diarrhoea carries on another day or two. By day two or three most people feel normal again, though appetite and bowels take a little longer to come back. In small children and older people the illness drags on and is harder to weather.
Having had it gives no lasting protection: there are many types of the virus and immunity to each is short-lived, so it is quite possible to catch it twice in one season. There is as yet no vaccine against norovirus.
How it is passed on
The virus leaves the body in stools and vomit and gets into someone else's mouth by way of hands, objects, food or water. Its infectiousness is extraordinary: a few viral particles are enough, an amount neither visible nor detectable. Hence the outbreaks in which dozens of people fall ill at once.
The usual routes are these:
- close contact with someone who has it — nursing them, sharing crockery, sharing a towel;
- touching door handles, taps, flush buttons or handrails and then touching your face;
- food prepared by someone with the infection, or by someone who has only just recovered;
- raw or undercooked shellfish, oysters above all, and contaminated water;
- breathing in the fine droplets thrown up during vomiting — which is why vomit is cleared up in gloves and a mask, not simply wiped over with a cloth.
A person is infectious from the first hours of the illness and stays so for at least two days after the vomiting and diarrhoea have stopped. The virus keeps coming out in the stool for longer still, up to a couple of weeks, so handwashing does not lapse just because you feel perfectly well.
Looking after yourself and your child at home
There is no treatment that kills the virus, and antibiotics are useless here: they have no effect on viruses and will only add to the diarrhoea. It all comes down to replacing the fluid and salts being lost.
- Drink often and in small amounts. A large glass swallowed at once, when you feel sick, comes straight back; a mouthful every few minutes is absorbed. Water, weak tea and a light broth all serve.
- Use oral rehydration salts. The sachet from the pharmacy is made up exactly as the instructions say, in the stated volume of water. It beats plain water because it puts back the salts lost in the stool as well. It matters most for small children, older people and anyone with a long-term condition.
- Carry on breastfeeding or bottle feeding as usual. There is no need to stop. If the baby is being sick, offer smaller amounts more often. Make formula up at the normal strength, not weaker.
- Eat when you can. There is no special diet; it is easier to start with plain food and leave fatty and very spicy dishes for later. Forcing yourself is unnecessary — drinking is not.
- Rest and stay at home. That is also the only way not to spread the infection around.
- For aches and a temperature paracetamol at the usual dose is suitable; for a child, follow the leaflet for the children's preparation and go by weight.
A pharmacist will suggest a suitable rehydration preparation and check whether it clashes with your regular medicines. It is also worth asking a doctor if you take water tablets or medication for blood pressure or diabetes: with vomiting and diarrhoea these are sometimes paused for a while.
What is better not done
- Do not rehydrate on fruit juice or fizzy drinks. Sugary drinks pull water into the bowel and make the diarrhoea worse. Sports drinks are no substitute for rehydration salts.
- Do not give children medicines that stop diarrhoea. In an adult such a medicine is occasionally reasonable for a few hours — to get home, say — but never with blood in the stool or a high temperature, and better after a word with a pharmacist or doctor.
- Do not give aspirin to children or adolescents. In a viral illness it is not for them.
- Do not take anti-sickness tablets on a friend's recommendation. These medicines have their own restrictions, particularly in childhood.
- Do not rely on alcohol hand gel. It works poorly against norovirus. Soap and water are what is needed.
- Do not go back to work "nearly better". That is precisely how the infection moves through a workplace.
Recognising dehydration
This is the thing to keep an eye on. In an adult the warning signs are a dry mouth and thirst, dark strong-smelling urine, passing water less often than usual, dizziness on standing, weakness, headache and sunken eyes.
In a child of one or two the signs are different and need catching sooner: nappies stay dry longer than they should, the child is listless or, conversely, unusually fretful, cries without tears, has a sunken soft spot on the head and dry lips. A baby who turns away from breast and bottle during the illness also needs a doctor's attention.
In an older person dehydration may show itself as confusion and sudden weakness, and there may be no thirst at all. At separate risk are people with diabetes, kidney disease or heart failure, and anyone taking water tablets.
When to see a doctor
Contact a doctor the same day if:
- the signs of dehydration are not settling despite rehydration salts;
- the vomiting will not stop and no fluid stays down;
- the diarrhoea lasts more than a week, or the vomiting more than two days;
- there is blood in the stool or bleeding from the back passage;
- a high temperature persists for several days;
- the person who is ill has a weakened immune system, has had a transplant or is on chemotherapy;
- you are worried about a baby under a year old.
Call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine that is 112) if there is:
- vomiting of blood, or vomit that looks like coffee grounds;
- green vomit, or in a child yellow-green vomit;
- sudden severe tummy pain that makes speaking or moving impossible;
- a sudden severe headache, a stiff neck, pain on looking at bright light, or a rash that does not fade when pressed — vomiting can be the opening of meningitis, and that combination will not wait;
- blue, grey, pale or blotchy skin, lips or tongue — on brown and black skin this is easier to see on the palms and soles;
- serious difficulty breathing, or fast shallow breaths;
- confusion, unusual drowsiness, a child who is hard to wake;
- any suspicion that the person has swallowed something poisonous.
With signs like these, do not drive yourself to the emergency department: ask someone to take you or call an ambulance. Bring the list of medicines you take.
How to avoid passing it on
While you are ill and for two days afterwards:
- wash your hands with soap under running water after the toilet, after changing a nappy and before any food — thoroughly, for at least twenty seconds;
- do not cook for other people or lay the table;
- wash soiled clothes and bedding separately and hot, at 60 °C or above;
- wipe the toilet, the flush button, taps, light switches and door handles with a bleach-based product, not water alone;
- use your own towel;
- stay away from work, school and nursery, do not visit hospitals or care homes, and keep out of the swimming pool.
When clearing up vomit, put gloves on, soak the liquid up with kitchen paper, drop it into a bag and only then disinfect the surface. Air the room. The two-day rule after the last episode is not fussiness: those are exactly the days on which someone who already counts themselves better does most of the infecting.
Online consultation
With norovirus an online appointment has the advantage that nobody has to bring an ill person into a waiting room full of other patients. From your description the doctor will judge how much fluid has been lost, explain how and how much to give, help you work out whether any of your regular medicines should be paused for now, and tell you when watching should stop and hospital should start. They will also say how many days to stay off work and how to keep the rest of the household clear of it.
What an online appointment does not replace: examination and assessment when dehydration is marked, blood tests and a drip. If a baby's nappies are dry and the baby is listless, or an adult cannot keep down a single mouthful of water, the help needed is face to face and without delay.
This material is for information only and does not replace medical advice.
Consult with a doctor about Norovirus (vomiting bug)
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Online doctors for Norovirus (vomiting bug)
Discuss your symptoms and possible next steps for Norovirus (vomiting bug) with a doctor online.
