When Is the Stomach Flu Contagious?

Stomach flu (viral gastroenteritis) is highly contagious. And you may be able to spread it before you know you're sick and for two weeks after you recover.

The term "stomach flu" is common, but this illness isn't related to the actual flu (influenza, a respiratory illness). Gastroenteritis is caused by several viruses, including norovirus and rotavirus.

This article looks at the causes and symptoms of stomach flu, how the viruses are spread, when viral gastroenteritis is contagious, and what you can do if you or someone in your household is sick with stomach flu.

Woman tending to a young child who is laying in bed
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When Is Stomach Flu Contagious?

The contagious period is different depending on which virus causes the stomach flu.

  • Norovirus: Symptoms appear one to three days after exposure. You're contagious as soon as symptoms develop and for up to two weeks after you feel better.
  • Rotavirus: This virus is contagious even before symptoms appear and for up to ten days after you recover. Typically, symptoms start one to two days after exposure.

The typical recommendation is to return to daily activities only after you've been symptom-free for 24 hours. You're likely still contagious at that point, so preventive measures are important to keep from spreading it.

With both of these viruses, children are contagious for a longer period than adults.

Vaccinating Children

Rotavirus can be very serious and even deadly in younger children. You may want to ask your child's healthcare provider about a vaccine that prevents it.

Symptoms of Stomach Flu

Common stomach flu symptoms include:

  • Diarrhea, which is sometimes severe and watery
  • Vomiting
  • Nausea
  • Stomach pain
  • Fever
  • Headache
  • Body aches
  • Loss of appetite
  • Dehydration

Preventing dehydration is important, as you lose moisture through diarrhea, vomiting, and sweating due to a fever.

How Stomach Flu Spreads

Stomach flu is spread through contact with an infected person's stool or vomit. Common routes of infection for viral gastroenteritis are:

  • Sharing eating utensils
  • Eating improperly prepared foods
  • Drinking contaminated water
  • Kissing someone who is sick
  • Shaking hands with someone who is sick

You can also catch it by touching a contaminated surface and then touching your mouth or something you put in your mouth. This is called fomite transmission.

Stomach Flu Prevention

To prevent the spread of viral gastroenteritis, you should:

  • Wash your hands after using the bathroom or changing diapers, before and after preparing food, or when caring for someone who is sick.
  • Use hand sanitizer when soap and water aren't available or in addition to hand washing.
  • Thoroughly wash fruits and vegetables. To be extra safe, peel them.
  • Cook food thoroughly.
  • Don't allow sick people to prepare food or take care of others.
  • Thoroughly clean and disinfect high-touch surfaces (countertops, doorknobs) and anything the sick person has touched.
  • Wash linens and clothing the sick person has used.
  • Try not to touch your mouth or face, and teach your children not to touch theirs (or yours).

Staying away from sick people and keeping yourself and your sick family members home can help keep stomach flu from spreading, as well.

Summary

Stomach flu (viral gastroenteritis) is caused by viruses like norovirus and rotavirus. Symptoms include nausea, vomiting, diarrhea, stomach pain, fever, and weakness.

Stomach flu may be contagious for a couple of days before you have symptoms and up to two weeks after symptoms have cleared.

The virus is spread by direct or indirect contact with a sick person's stool or vomit. This includes kissing or touching a sick person or coming into contact with contaminated objects, surfaces, or food.

To prevent the spread, isolate, wash your hands, cook food thoroughly, and disinfect items the sick person has touched.

A Word From Verywell

The stomach flu is unpleasant, but people recover without any complications. If you or someone you care about seems to be especially sick or symptoms linger for longer than expected, talk to your healthcare provider.

Meanwhile, being smart about cleanliness and limited contact can go a long way toward keeping the virus from spreading.

Frequently Asked Questions

  • Is stomach flu contagious through air? Or through saliva?

    Yes, stomach flu can be spread through the air or saliva, especially soon after someone vomits. Then, as they breathe, sneeze, or cough, particles may carry the virus to you. You may also catch it from kissing and sharing utensils.

  • How long should I stay home from work with the stomach flu?

    People can generally return to normal activities once they are symptom-free for 24 hours. Depending on the cause of the stomach flu, you could still be contagious for up to two weeks after symptoms have cleared.

  • Does COVID-19 cause a stomach flu?

    No, but it can cause digestive symptoms such as nausea, vomiting, and diarrhea. Unlike the stomach flu, COVID also causes breathing problems, sore throat, cough, and the loss of taste or smell.

    A COVID test can help you figure out what's causing your digestive sypmtoms.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Norovirus: Symptoms.

  2. Oude Munnink BB, Van der Hoek L. Viruses causing gastroenteritis: the known, the new and those beyond. Viruses. 2016;8(2). doi:10.3390/v8020042

  3. Centers for Disease Control and Prevention. Rotavirus: Symptoms.

  4. Vesikari T. Rotavirus vaccination: a concise review. Clin Microbiol Infect. 2012;18 Suppl 5:57-63. doi:10.1111/j.1469-0691.2012.03981.x

  5. Parashar UD, Nelson EA, Kang G. Diagnosis, management, and prevention of rotavirus gastroenteritis in children. BMJ. 2013;347:f7204. doi:10.1136/bmj.f7204

  6. GI Society: Canadian Society of Intestinal Research. Gastroenteritis (stomach flu).

  7. California Department of Health Services. Acute viral gastroenteritis (or "stomach flu").

  8. National Institutes of Health. NIH scientists discover norovirus and other "stomach viruses" can spread through saliva.

  9. Center for Disease Control and Prevention. COVID-19.

Additional Reading

By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.