Norovirus: Common Questions Answered
Norovirus: straight answers to the questions people actually ask, with the figures behind them.
A very contagious virus that causes sudden vomiting and diarrhea, often called the "stomach bug."
Key takeaways
- Symptoms start: 12 to 48 hours after exposure
- Usual length: 1 to 3 days
- Most useful single change: Sip water, oral rehydration solution or broth often to replace lost fluids.
- Commonest mistake: Cooking or serving food for others while sick and for 2 days afterward.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
What is Norovirus?
A very contagious virus that causes sudden vomiting and diarrhea, often called the "stomach bug."
Why does it matter?
It is the leading cause of vomiting, diarrhea and foodborne illness in the US, and it spreads easily through food, surfaces and close contact.
Symptoms start for Norovirus?
12 to 48 hours after exposure.
Usual length for Norovirus?
1 to 3 days.
Hand cleaning for Norovirus?
Soap and water for at least 20 seconds; hand sanitizer alone does not work well.
Cleaning surfaces for Norovirus?
A bleach solution or an EPA-registered disinfectant labeled for norovirus.
What is the single most useful thing to do?
Sip water, oral rehydration solution or broth often to replace lost fluids.
What is the most common mistake?
Cooking or serving food for others while sick and for 2 days afterward.
When should I see a doctor?
Call your doctor if vomiting or diarrhea lasts more than a few days, there is blood in the stool, or a baby, older adult or someone with a chronic condition cannot keep fluids down. Call 911 for signs of severe dehydration, such as very little or no urine, dizziness when standing, fainting, confusion, or a child who is unusually sleepy or fussy and cries without tears.
More questions, answered
Is norovirus the same as food poisoning?
Norovirus is the leading cause of foodborne illness in the US, but it also spreads directly from person to person and through contaminated surfaces. Other germs, such as Salmonella and E. coli, can also cause food poisoning, often with fever or bloody diarrhea, and some of those need different care.
Is there a vaccine for norovirus?
Not yet. Vaccines are being studied, but none is currently available in the US. Prevention depends on hand washing, careful food handling, cleaning and staying home while sick.
How long am I contagious?
You are most contagious while you are sick and in the first few days after you recover. The virus can remain in stool for two weeks or more, so keep washing your hands carefully with soap and water, especially before handling food for others.
Why does hand sanitizer not work well?
Norovirus lacks the fatty outer coat that alcohol damages in many other viruses, so it is more resistant. Washing with soap and water for at least 20 seconds physically removes virus particles, which is why it is recommended over sanitizer alone.
Can I get norovirus from my pet?
Human norovirus is not known to be spread by pets. Pets can still track contaminated material around the house, so keep them away from areas that are being cleaned up after vomiting or diarrhea.
Should I stop eating out during outbreaks?
Not usually. Restaurants are required to follow food safety rules, including keeping sick workers home. If you hear of an outbreak linked to a specific place, follow health department advice, and always wash your hands before eating.
Related topics
- The Evidence on Infection Prevention at Home, Without the Hype (Immunity)
- What the Guidance Really Says About Diarrhea (Digestive Health)
- Travelers' Diarrhea: What the Evidence Actually Says (Travel Health)
- Common Childhood Infections: What the Evidence Actually Says (Children's Health)
Where to go next
- New to Norovirus? Start Here
- Norovirus at a Glance
- Norovirus — the reference entry
- Infectious Diseases: The Complete Guide
- Strep Throat: What Published Guidance Supports
- Hepatitis A: Sorting the Evidence From the Noise
When to speak to a doctor
Call your doctor if vomiting or diarrhea lasts more than a few days, there is blood in the stool, or a baby, older adult or someone with a chronic condition cannot keep fluids down. Call 911 for signs of severe dehydration, such as very little or no urine, dizziness when standing, fainting, confusion, or a child who is unusually sleepy or fussy and cries without tears.
Where this comes from
- CDC — About Norovirus
- EPA — List G: EPA's Registered Antimicrobial Products Effective Against Norovirus
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
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