Norovirus, often called the winter vomiting bug, is the most common cause of gastroenteritis worldwide. It causes sudden vomiting, diarrhoea and stomach cramps, usually lasting 1 to 3 days. It spreads extremely easily, and alcohol hand gel doesn’t reliably kill it, so washing hands with soap and water and cleaning with bleach-based products are essential.
Symptoms
- Sudden nausea and vomiting (often projectile)
- Watery diarrhoea
- Stomach cramps
- Mild fever, headache, aching limbs
- Symptoms usually start 12 to 48 hours after exposure
How it spreads
- Close contact with infected people
- Touching contaminated surfaces then your mouth
- Contaminated food or water
- Tiny droplets from vomit
Very few virus particles are needed to cause infection, and the virus survives on surfaces for days.
Home treatment
- Drink plenty of fluids; take small sips often
- Oral rehydration solutions help, especially for children and older adults
- Eat when you feel able: plain foods
- Rest
- Paracetamol for aches if needed
- Antibiotics don’t work; norovirus is a virus
Stay home for 48 hours
Stay off work, school or nursery until 48 hours after the last episode of vomiting or diarrhoea. Health and care workers must follow this strictly. Avoid visiting hospitals and care homes.
When to get medical help
- Signs of dehydration: very little urine, dizziness, dry mouth, sunken eyes, drowsy child
- Blood in diarrhoea
- Vomiting that won’t stop, or unable to keep fluids down
- Symptoms lasting more than a week
- Babies, frail older adults or people with weak immunity
Outbreak control on wards and in care homes
- Isolate symptomatic patients in single rooms or cohort bays; close bays if needed
- Use gloves and aprons; wash hands with soap and water after contact
- Clean with chlorine-based (bleach) products, especially toilets, commodes and high-touch surfaces
- Remove vomit and faeces promptly and safely
- Restrict visitors and staff movement between areas
- Exclude symptomatic staff until 48 hours symptom-free
- Inform infection prevention and control
Frequently asked questions
Can you get norovirus twice in one season?
Yes. Immunity is short-lived and there are many strains.
Is there a norovirus vaccine?
Not yet widely available; vaccines are in development.
Related reading: Hand hygiene · Dehydration in children · Healthcare waste
Checked against NHS guidance on norovirus. Updated 5 November 2026.