Norovirus - Frequently Asked Questions

What are noroviruses?
Noroviruses are one of the most common causes of gastroenteritis (stomach bugs). In the past, noroviruses have also been called 'winter vomiting viruses', 'small round structured viruses' or 'Norwalk-like viruses'. They belong to a group of viruses called 'caliciviruses'.

What are the symptoms of norovirus infection ?
Symptoms include:

• Nausea (often sudden onset)
• Vomiting (often projectile)
• Watery diarrhoea.   

Some people may have a raised temperature, chills, muscle aches and headaches. Symptoms begin around 12 to 48 hours after becoming infected. The illness is usually brief, with symptoms lasting only about 1 or 2 days. Most people make a full recovery within 1-2 days, however some people (usually the very young or elderly) may become very dehydrated and require hospital treatment.

Are noroviruses contagious?
Noroviruses are very contagious and can spread easily from person to person. Both faeces and vomit of an infected person contain the virus and are infectious. People infected with norovirus are contagious from the moment they begin feeling ill to 2/3 days after recovery. Some people may be contagious for as long as 2 weeks after recovery.

It is important for people to use good handwashing and other hygienic practices after they have recently recovered from norovirus illness. In addition, noroviruses are very resilient and can survive in the environment (on surfaces etc) for a number of weeks.

How does norovirus spread?
People can become infected with the virus in several ways, including: 

• Contact with an infected person e.g. when caring for someone with norovirus infection.
• Contact with contaminated surfaces or objects and then touching their mouth or mucous membranes.  
• In hospitals, healthcare workers and hospital visitors can spread the virus to other patients or contaminate surfaces through hand contact. 
• Consuming contaminated food or water.

Who is at risk of getting norovirus?
Norovirus infection affects people of all ages. There are many different strains of norovirus, and immunity is short-lived. Therefore people can get norovirus infection more than once.

How is norovirus treated?
There is no specific treatment for norovirus apart from letting the illness run its course. It is important to drink plenty of fluids to prevent dehydration.

If I'm suffering from norovirus, how can I prevent others from becoming infected?
Good hygiene is important in preventing others from becoming infected - this includes thorough hand washing before and after contact. Food preparation should also be avoided until 3 days after symptoms have gone altogether.

Are there any long-term effects?
No, there are no long-term effects from norovirus. 

What can be done to prevent infection?
It is often impossible to prevent infection, however, taking good hygiene measuresaround someone who is infected can decrease your chance of getting infected.

• Frequent handwashing including before eating or preparing food.
• Thoroughly clean and disinfect contaminated surfaces immediately after an episode of illness by using a bleach-based household cleaner.
• Immediately remove and wash clothing or linens that may be contaminated with virus after an episode of illness (use hot water and soap).
• Flush or discard any vomit and/or faeces in the toilet and make sure that the surrounding area is kept clean.

Detailed cleaning guidance is available on our "How to clean up and decontaminate after someone has vomited" page. 

Gastroenteritis due to norovirus can be very disruptive to organisations and businesses. The Information for Employers section provides guidance on the management of noroviral infection for employers.

Why does norovirus often cause outbreaks? 

• It is easily spread from one person to another

and

• It is able to survive in the environment for many days

Outbreaks of norovirus are reported frequently anywhere that large numbers of people congregate for periods of several days (such as hospitals, schools, residential and nursing homes, cruise ships and hotels). This is because these places provide an ideal environment for the spread of the disease. Healthcare settings (hospitals and nursing homes) tend to be particularly affected by outbreaks of norovirus.   

How can norovirus outbreaks be stopped?
The best way to control an outbreak is:

• Segregation/Isolation of infected patients from non-infected patients (usually until at least 48 hours after their symptoms have ceased).
• Good infection control
  • Handwashing
  • Wearing gloves and aprons, especially when dealing with bedpans etc.
  • Cleaning and disinfection of areas where there are cases of norovirus infection helps reduce environmental contamination.

Updated: 9 January 2019