Norovirus (winter vomiting bug): symptoms, how long it lasts and how it spreads

The NHS says norovirus can be very unpleasant but usually gets better in about 2 days, and that you will usually start to feel better in 2 to 3 days. NHS inform says the symptoms appear 1 to 2 days after you become infected and typically last for up to 2 or 3 days, and that norovirus usually clears up by itself in a few days.

Call 111 if you or your child have diarrhoea for more than 7 days or vomiting for more than 2 days, according to the NHS.

NHS inform says norovirus is most infectious from the start of symptoms until 48 hours after all symptoms have stopped, and you may also be infectious for a short time before and after this. It says you can get norovirus more than once because the virus is always changing and the body cannot build up long-term resistance.

The NHS says norovirus is caused by a virus that spreads through poo and can spread to others very easily. NHS inform adds that it spreads very easily in public places such as hospitals, nursing homes and schools, and that the virus can survive outside the body for several days on contaminated surfaces.

• close contact with someone who has norovirus, including breathing in small particles of the virus (NHS inform)

• touching surfaces or objects that have the virus on them, then touching your mouth

• eating food prepared or handled by someone with norovirus

• drinking unclean water or eating infected food, such as oysters from an unreliable source

The NHS says the main symptoms usually start suddenly and may include feeling sick, being sick (vomiting) and diarrhoea. You may also have a high temperature, a headache, tummy pain and body aches and pains. NHS inform describes suddenly feeling sick, projectile vomiting and watery diarrhoea, with a slight fever, headaches, painful stomach cramps and aching limbs.

The NHS says you can usually treat norovirus at home, and the most important thing is to have lots of fluids to avoid dehydration. NHS inform says there is no treatment for norovirus, so you have to let it run its course, and antibiotics will not help because it is caused by a virus.

NHS inform says to stay off work or school until at least 48 hours after the symptoms have stopped and to avoid visiting anyone in hospital during this time. The NHS gives the following measures.

• wash hands with soap and water after the toilet or changing nappies and before preparing, serving or eating food; alcohol hand gels do not kill norovirus

• wash clothes and bedding with poo or vomit on them at 60C, separately from other laundry

• clean toilet seats, flush handles, taps and bathroom door handles; NHS inform suggests a bleach-based household cleaner

• avoid contact with others as much as possible

• do not go to school, nursery or work, or visit hospitals and care homes, until you have not been sick or had diarrhoea for 2 days

• do not share towels and flannels (NHS inform)

The NHS says babies and young children, especially under a year old, have a greater risk of becoming dehydrated (NHS inform). Call 111 now if you are worried about a baby under 12 months, your child stops breast or bottle feeding while ill, or a child under 5 has signs of dehydration such as fewer wet nappies. Do not give children under 12 medicine to stop diarrhoea, and do not give aspirin to children under 16.

NHS inform advises babies to continue to feed as usual, and says to avoid fizzy drinks or fruit juice for children as it can make diarrhoea worse.

The NHS and NHS inform norovirus pages do not give pregnancy-specific advice. Tommy's, a UK pregnancy charity, says diarrhoea in pregnancy can be caused by a tummy bug or food poisoning, and both Tommy's and the NHS say loperamide is not usually recommended in pregnancy. Speak to your midwife, GP or NHS 111 if you are pregnant and cannot keep fluids down or have a fever.

NHS inform says you do not usually need to see your GP, and to avoid going to the surgery because norovirus spreads easily. Phone your GP practice or NHS 111 if you are concerned. The NHS says to call 111 now in the situations below and 999 or A&E for the emergency signs.

• you are worried about a baby under 12 months, or your child stops feeding while ill

• a child under 5 has signs of dehydration, such as fewer wet nappies

• signs of dehydration continue after oral rehydration sachets

• you keep being sick and cannot keep fluid down

• bloody diarrhoea or bleeding from the bottom

• diarrhoea for more than 7 days or vomiting for more than 2 days

• 999 or A&E: vomiting blood or vomit like ground coffee, green vomit in adults, a stiff neck and pain looking at bright lights, a sudden severe headache or tummy ache, blue or blotchy skin, severe difficulty breathing, or confusion

Most norovirus is managed at home, with a pharmacist able to recommend oral rehydration powder if you have signs of dehydration. NHS 111 is the route for the warning signs above. NHS inform says to avoid going to the GP surgery because norovirus can spread to others, so phone first.