Norovirus is a highly contagious virus that inflames the stomach and bowel, leading to acute gastroenteritis. Common in settings like healthcare facilities, schools, and cruise ships, it poses significant health challenges. While most individuals recover within a few days, some may experience prolonged effects on gut health.
The latest NHS figures show twice as many cases as last year and more than 1,000 people a day in the hospital with norovirus in England last week.
Dr Angad Dhillon, a Doctify rated consultant gastroenterologist , says there are four groups of people most at risk from the virus.
Dr Dhillon said: “Norovirus is often called ‘stomach flu,’ but it’s not related to influenza at all – it’s a completely different virus with unique symptoms and treatment needs. As few as 10 virus particles can cause a norovirus infection, making it one of the most contagious viruses, and symptoms typically appear 12–48 hours after exposure and last 1–3 days.
“Individuals are contagious from the moment symptoms begin until at least 48 hours after they resolve. However, the virus can remain in the stool for up to two weeks or more after recovery, making continued hygiene practices essential.”
Symptoms of norovirus include:
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Nausea and vomiting: Sudden onset, often severe
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Diarrhoea: Watery stools leading to dehydration
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Stomach cramps: Abdominal pain and discomfort
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Additional symptoms: Low-grade fever, chills, muscle aches, and fatigue
When it comes to transmission, norovirus spreads through direct contact with an infected person, via contaminated surfaces (as the virus can survive on surfaces for days if not properly disinfected) or through contaminated food and water, especially raw or undercooked shellfish and produce.
Dr Dhillon says certain groups are more susceptible to severe norovirus infections, including:
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Young children: Due to developing immune systems
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Elderly individuals: Owing to age-related immune decline and potential comorbidities
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Immunocompromised persons: Including those undergoing chemotherapy or with chronic illnesses
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Pregnant women: Dehydration can pose risks to both mother and fetus
Dr Dhillon said: “Hand sanitisers aren’t enough against norovirus – thorough handwashing with soap and water is the most effective prevention method.To reduce the risk of contracting norovirus, hand hygiene is key… Wash hands frequently with soap and water, as alcohol-based sanitisers are less effective against norovirus. Food safety is also important – thoroughly cook seafood and wash fruits and vegetables before consumption. Staying home when ill is also advised when ill, so you should avoid public places and close contact with others when experiencing symptoms and for at least 48 hours after recovery.
Dr Dhillon added: “Norovirus is a common but preventable cause of gastroenteritis. By understanding its transmission, recognising symptoms, and implementing proper care and hygiene practices, individuals can recover effectively and minimise the risk of spreading the virus. If symptoms persist or worsen, consulting a healthcare professional is advisable”.