About Norovirus

Page last updated 6/3/2024.

What is Norovirus?

Norovirus is a very contagious virus that causes vomiting and diarrhea. People of all ages can get infected and sick with norovirus.

How is Norovirus Transmitted (Spread)?

Norovirus can be found in the stool and vomit of people who are infected. Norovirus is spread when someone ingests the virus (usually in amounts too small to see) through:

  • Person-to-person contact: Norovirus can spread from close, personal contact with an infected person, such as caring for or sharing food or eating utensils with someone who is ill. Norovirus is very contagious. People can spread the virus even after they feel better.
  • Eating contaminated food or drink: A person infected with norovirus can contaminate food with their bare hands if they have norovirus particles on their hands. Food may also be contaminated if it is placed on a surface that has norovirus particles on it or if tiny drops of vomit from an infected person land on food. It is also possible, but less likely, that food is grown, harvested, or irrigated with contaminated water.

People with norovirus should stay home until they no longer experience vomiting or diarrhea. They should not prepare food or provide care for others while they are ill and for at least 2 days after symptoms stop to avoid further transmission.

What Are The Symptoms Of Norovirus?

Symptoms develop 12 to 48 hours after being exposed to norovirus. Symptoms usually last 1 to 3 days.

Symptoms can include:

  • Diarrhea
  • Vomiting
  • Nausea
  • Stomach pain
  • Fever
  • Headache
  • Body aches

How Is Norovirus Diagnosed?

A doctor can determine if you are likely to have norovirus based on your symptoms alone. There is a stool test for norovirus but that is usually not necessary.  

How Is Norovirus Treated?

There is no specific treatment for norovirus infection. Most people get better on their own within 1-2 days. If you experience diarrhea or vomiting, drink plenty of liquids to prevent dehydration. Preventing dehydration is especially important for children, elderly, and people with weak immune systems. People with severe dehydration may require hospitalization.

How Can Norovirus Be Prevented?

  • The best way to prevent norovirus is by practicing proper hand hygiene and disinfecting contaminated surfaces.
  • Protect yourself and others from norovirus by washing your hands thoroughly with soap and water (for at least 20 seconds):
    • After using the toilet and changing diapers
    • Before eating, preparing, and handling food
    • Before giving yourself or someone else medicine
  • Promptly clean up accidents involving vomit or feces.
    • Protect your clothes and wear disposable gloves. Use a mask if available.
    • Remove the vomit or feces carefully with paper towels.
    • Then disinfect the area using a bleach-based household cleaner as directed on the product label.
    • Discard contaminated items that are disposable.
    • Wash contaminated clothing with detergent using hot water and hot dry settings.
    • Wash your hands with soap and water afterwards.
  • Frequently disinfect commonly touched surfaces, such as kitchen and bathroom surfaces, doorknobs, handles, tables, chairs, phones, etc.
  • Norovirus can be found in your vomit or feces even before you start feeling sick. The virus can also stay in your feces for two weeks or more after you feel better. It is important to continue washing your hands often during this time.
  • Hand sanitizer does not work well against norovirus. Handwashing is always best, and hand sanitizer should not be used as a substitute to handwashing.

Local Outbreaks in San Diego County


Resources For Healthcare Professionals

County of San Diego


California Department of Public Health (CDPH)


For more information, contact the Epidemiology Unit at 619-692-8499 or send us an e-mail.