Introduction

Norovirus is a highly contagious virus that causes stomach and intestinal inflammation, resulting in symptoms such as vomiting and diarrhoea. It is sometimes called the “winter vomiting bug” because outbreaks are more common in cooler months, due to its ability to thrive in lower temperatures.¹ Norovirus is significant because it spreads quickly and can make people feel very unwell, though most recover within a few days. 

While anyone can contract norovirus, young children and the elderly may experience more severe illness or face higher risks of complications. 

What is norovirus?

Norovirus is one of the most common causes of gastroenteritis worldwide. As it affects the stomach and intestines, common symptoms include nausea, vomiting, watery diarrhoea, and stomach pain. In some cases, people may also experience a mild fever, headache, and body aches.

How norovirus spreads:

• Person to person: Close contact with someone who is infected, such as caring for a sick relative or friend
• Contaminated food or water: Sharing food or drinks that have been contaminated with the virus
• Contaminated surfaces: Touching objects or surfaces that have the virus on them, then touching your mouth

Norovirus is extremely contagious and only requires a small number of viral particles to cause an infection. Outbreaks are particularly common in close-contact communities, such as schools, care facilities, and nursing homes. 

Good hand hygiene, proper food preparation, and regular cleaning of surfaces are essential measures to help reduce the risk of catching or spreading norovirus. 

Norovirus in children

Why are children commonly affected?

Children are often affected by norovirus because the virus spreads easily in crowded places, such as schools and daycare centres. Young children frequently have close contact with each other, may not wash their hands thoroughly, and often touch shared toys and surfaces. These factors create a high risk for norovirus outbreaks among this age group, which can then also be brought into households and into the wider community. 

Typical symptoms in children

The most common symptoms of norovirus in children include:

• Nausea and vomiting (children are slightly more likely than adults to experience vomiting as their main symptom)
• Watery diarrhoea 
• Sudden stomach cramps
• Mild fever and body aches 

Symptoms usually begin 12 to 48 hours after exposure and last for one to three days. Most children recover fully within this timeframe.

Risks for young children (dehydration and when to see a doctor)

Young children are at risk of dehydration because they lose fluids quickly through vomiting and diarrhoea, and may not be able to drink enough to replace lost fluids. Signs of dehydration include:

• Crying with few or no tears
• Unusual sleepiness or irritability 
• A sunken soft spot in infants 
• Decreased urination 

If a child cannot keep down liquids, has a high fever, is unusually sleepy, has infrequent urination, or becomes increasingly fussy, it is important to contact a doctor immediately. 

Norovirus in adults 

Typical symptoms in adults

In adults, norovirus symptoms are similar to those seen in children and may include: 

• Vomiting
• Diarrhoea (adults tend to have more diarrhoea than vomiting)
• Nausea and stomach pain
• Mild fever, headache, and muscle aches 

Symptoms generally appear 12 to 48 hours after exposure and last between one to three days. 

How norovirus might disrupt daily life

Although short-lived, norovirus can cause significant disruption. The sudden and severe onset of symptoms often leads to missed work, school, and social activities. As the virus is highly contagious, adults who are sick should avoid contact with others, including staying home from work or school, and should not prepare food for others for at least 48 hours after symptoms have resolved.

Tips for managing symptoms at home

• Rest and stay at home to prevent spreading the virus
• Drink plenty of fluids (water, clear soups, oral rehydration solutions) to avoid dehydration
• Gradually reintroduce bland foods as nausea starts to improve (toast, rice, bananas, crackers)
• Practise good hand hygiene and disinfect frequently touched surfaces (especially in shared bathrooms or kitchens)
• Avoid sugary, caffeinated, or alcoholic drinks, as these can worsen symptoms
• You may take over-the-counter medications for pain or fever if needed, but anti-diarrhoeal medications are not usually recommended

If symptoms are severe, persistent, or you are unable to keep fluids down, it is important to seek medical help.

Norovirus in older adults

Reasons older adults are at higher risk

Older adults are more likely to experience severe effects from norovirus for several reasons:

• Weaker immune systems: As people age, the immune system becomes less effective at fighting infections — a process called immunosenescence²
• Chronic conditions: Underlying health conditions, such as heart disease, diabetes, or kidney problems, can slow down your rate of recovery
• Congregate living: Outbreaks are especially common and more difficult to control in settings like care homes, where older residents are in close contact with each other

Why symptoms may be more severe

Older adults often experience more severe or prolonged norovirus symptoms. While younger people usually recover within two or three days, older adults may be unwell for four days or more, especially those over 85 years old. Common symptoms (vomiting, diarrhea, stomach pain, and fatigue) can be more intense and last longer in older adults, which increases the risk of complications. 

Possible complications (dehydration, hospitalisation)

• Dehydration: The greatest risk for older adults is dehydration, caused by ongoing vomiting and diarrhoea. Older adults naturally have a lower fluid reserve, and pre-existing health conditions may further worsen symptoms. Severe dehydration can lead to confusion, low blood pressure, kidney problems, or, in rare cases, death
• Hospitalisation: Hospitalisation rates for norovirus are higher in older adults than in other age groups. Among those hospitalised, a significant number may require intensive care. Norovirus also causes a high proportion of illness outbreaks in care homes and hospitals, leading to increased hospital admissions
• Other complications: There may be longer-term consequences, such as a higher chance of post-infectious irritable bowel syndrome or an increased risk of severe effects in patients with organ transplants or weakened immune systems³

Importance of early medical attention for seniors:

Older individuals with norovirus should seek medical attention promptly if:

• They show signs of dehydration (dizziness, confusion, decreased urination, very dry mouth, weakness, or fainting) 
• Vomiting and diarrhoea persist, and they cannot keep fluids down
• There are additional symptoms, such as high fever or blood in stool

Getting help quickly can prevent serious complications. Allow for the timely use of intravenous fluids if needed, and lower the risk of life-threatening outcomes. With early intervention, most older people recover fully, but medical care is crucial when symptoms are severe or prolonged.⁴

Prevention for all ages

Keeping everyone safe from norovirus relies on everyday habits and extra care, especially in households with children or elderly members.

Handwashing and hygiene tips

• Wash hands thoroughly and often: Use soap and water for at least 20 seconds, especially after using the toilet, changing diapers, and before preparing or eating foodHand sanitisers are less effective against norovirus than simple handwashing with soap and water
• Remind children to wash well: Help children wash their hands properly, as they may not do an effective job on their own
• Clean and disinfect surfaces: Wipe down frequently touched surfaces, such as bathroom fixtures, door handles, and kitchen counters

Safe food preparation and handling

• Wash fruits and vegetables thoroughly: Rinse produce under running water before eating or cooking
• Cook seafood thoroughly: Shellfish, like oysters, should be cooked well, as norovirus can survive in undercooked seafood
• Avoid preparing food if sick: Anyone who has norovirus symptoms should not prepare food for others or care for vulnerable individuals for at least 48 hours after symptoms stop

Special precautions in homes with children or older adults

• Isolate sick individuals when possible: Move those who are ill to a separate room
• Wash contaminated items promptly: Wash bedding, clothes, and towels that may be contaminated with vomit or stool, using hot water and detergent
• Monitor for dehydration: Pay close attention to infants, toddlers, or senior family members for signs of dehydration
• Use gloves and extra care when cleaning up: Wear disposable gloves and use proper disinfectants, especially when caring for a baby or an older member

These steps are proven to significantly reduce the risk of norovirus infection and its spread within households and communities, helping to protect the most vulnerable. 

When to seek medical help

Knowing when to seek medical care is critical, especially for young children and older adults who can get sick quickly. Most people recover from norovirus without seeing a doctor, but certain warning signs indicate complications and require prompt medical attention.

Warning signs across age groups:

• Persistent vomiting
• Signs of dehydration
• Blood in stool or vomit
• High fever
• Inability to keep fluids down
• Worsening symptoms or underlying health conditions (e.g., heart problems, diabetes, kidney disease, etc.)

Early intervention and medical monitoring may prevent serious complications. 

Summary

Key Points to Remember about Norovirus and Age

• Norovirus causes vomiting and diarrhoea that usually resolve in a few days
• It spreads very easily and can affect anyone, but children and seniors are most vulnerable to complications
• Dehydration is the main danger, especially in infants and seniors
• Good hygiene and careful food handling are important in preventing serious illness
• Most people can recover fully, but extra caution is important for children and seniors