Many families first notice norovirus when a child becomes unusually quiet or pale before vomiting.
According to the Statens Serum Institut (SSI) in Denmark, the virus is widespread during winter, when people spend more time indoors and share close spaces.
This creates ideal conditions for the infection to move quickly through households, schools and workplaces.
If you become ill, the first task is to rest and keep hydrated.
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Doctors recommend drinking whatever fluids you manage to keep down, but taking them slowly to avoid worsening nausea.
SSI explains that dehydration is the main risk, especially for very young children and older adults.
Some people find it helpful to keep a glass of water nearby and take small sips every few minutes. Light snacks can be added once the stomach settles.
Families often rotate laundry and cleaning duties because fresh clothes and frequent handwashing reduce the chance of infecting others in the home.
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Recognising symptoms
Norovirus does not usually give early warning. Many people first feel a wave of queasiness before rapid vomiting or loose stools.
SSI notes that most cases last only a short time, although children may need longer before their appetite and energy return.
The illness tends to be intense but brief. Some experience only nausea while others deal with repeated episodes of vomiting.
A typical course is around one to two days, though the weakness can linger slightly longer.
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Because the symptoms resemble other stomach infections, people sometimes struggle to identify the cause.
However, SSI highlights that norovirus typically appears suddenly and moves quickly through groups of people, which often points to a shared exposure.
How it spreads
Research from SSI shows that the virus can persist on indoor surfaces long after the initial accident.
This includes carpets, bathroom floors and kitchen counters that are touched frequently during the day.
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Indirect contact is therefore a major route of infection.
Unlike bacteria, this virus is not easily removed with standard alcohol-based cleaners. Chlorine-based products work better, according to official guidance.
The virus can also travel through contaminated food. It was observed in a study published in PLOS Currents, where green coral lettuce was found to carry the virus.
Once symptoms fade, health authorities advise waiting a full two days before returning to school or work to reduce the risk of passing the virus to others.
If symptoms worsen or you cannot keep fluids down, it is important to contact a doctor for medical advice.
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Sources: Statens Serum Institut, and PLOS Currents.