When Is the Stomach Flu Contagious?

Viral gastroenteritis, also known as stomach flu, is an infectious disease that causes symptoms such as vomiting, diarrhea, nausea, fever, and weakness. Stomach flu is contagious when symptoms appear and even well after the symptoms have cleared.

This article looks at the causes of stomach flu as well as how the virus is spread from person to person. It also explains 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
Image Source / Getty Images

When You Are Contagious

Viral gastroenteritis can be caused by several different viruses. The two most common are:

  • Norovirus: This is the most common cause of stomach flu. Symptoms appear one to three days after exposure, and you are contagious as soon as symptoms develop.
  • Rotavirus: This virus is contagious even before symptoms appear and for up to two weeks after you recover. Typically, symptoms start one to two days after exposure.

People with viral gastroenteritis are advised to return to daily activities only after they have been symptom-free for 24 hours. Even so, you may still be contagious three days after you have recovered and can potentially spread the infection for up to two weeks.

With both of these viruses, children can spread the infection for a longer period than adults.

Recap

Norovirus and rotavirus are the two most common causes of stomach flu. Both are contagious the moment you develop symptoms and can remain contagious for up to two weeks after you have recovered.

How Stomach Flu Spreads

Stomach flu is spread through contact with an infected person's stool or vomit. This includes hand-to-mouth behaviors in which you touch something and bring your hand to your mouth.

There are several common routes of infection for viral gastroenteritis:

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

The virus can also be passed through fomite transmission, meaning through contact with objects or surfaces that have been contaminated with the virus.

Recap

Stomach flu is spread through contact with an infected person's stool or vomit, either directly from person to person or indirectly through contaminated objects or surfaces.

Prevention Methods

There are several ways to prevent the spread of viral gastroenteritis in your home:

  • Wash your hands after using the bathroom or changing diapers. You should also wash your hands before and after preparing food or when caring for someone who is sick. Use hand sanitizer if soap and water aren't available.
  • Wash fruits and vegetables thoroughly. You can also peel them to be extra safe.
  • Cook food thoroughly when someone in the household is sick.
  • Limit the movement of people who are sick. Don't allow them to prepare food or care for others.
  • Clean and disinfect surfaces thoroughly as well as anything the sick person has touched.
  • Wash linens and clothing that have come into contact with an ill family member.
  • Avoid bringing your hand to your mouth. Try to teach the same to your children.

Recap

To prevent the spread of stomach flu, wash your hands frequently with soap and water. Thoroughly wash fruits and vegetables and disinfect any surface or object the sick person has come into contact with. Cook foods through and avoid hand-to-mouth behaviors.

Summary

Viral gastroenteritis, also called the stomach flu, is caused by viruses like norovirus and rotavirus. People with stomach flu typically experience nausea, vomiting, diarrhea, stomach pain, fever, and weakness.

The virus is spread by direct or indirect contact with a sick person's stool or vomit. This includes kissing or touching someone who is sick or coming into contact with utensils, surfaces, or beddings that have been contaminated.

Viral gastroenteritis is contagious the moment symptoms appear and up to two weeks after symptoms have cleared. To prevent the spread of infection, isolate the sick individual, wash your hands frequently, and cook food thoroughly. You should also disinfect any surfaces or objects the sick person has come into contact with.

A Word From Verywell

The stomach flu is unpleasant to suffer through. Fortunately, most people recover without any complications.

With that said, rotavirus can be very serious and even deadly in younger children. Fortunately, there is a vaccine available to prevent infections. The vaccine series should start before the child is 15 weeks old. Children should receive all doses before they turn 8 months of age.

Frequently Asked Questions

  • 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.

  • How do you get the stomach flu?

    A stomach virus is spread by contact with an infected person's stool or vomit. The transmission can either be direct (through physical contact with a sick person) or indirect (touching a contaminated object or surface). Hand-to-mouth behaviors enable the spread of the virus. 

  • Does COVID-19 cause a stomach flu?

    Nausea, vomiting, and diarrhea are not the most common COVID symptoms, but they do occur. Unlike the stomach flu, COVID can also cause difficulty breathing, sore throat, cough, and the loss of taste or smell. A COVID test can establish if COVID is the cause of your gastrointestinal sypmtoms.

Was this page helpful?
8 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. Graves NS. Acute gastroenteritis. Prim Care. 2013;40(3):727-41. doi:10.1016/j.pop.2013.05.006

  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. Updated norovirus outbreak management and disease prevention guidelines. MMWR Recomm Rep. 2011;60(RR-3):1-18.

  4. Lee RM, Lessler J, Lee RA, et al. Incubation periods of viral gastroenteritis: a systematic review. BMC Infect Dis. 2013;13:446. doi:10.1186/1471-2334-13-446

  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. Stuempfig ND, Seroy J. Viral Gastroenteritis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.

  7. 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

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

Additional Reading
  • "Viral Gastroenteritis". MedlinePlus 7 Nov 14. US National Library of Medicine. US Department of Health and Human Services. National Institutes of Health. 
  • "Preventing Norovirus Infection". Norovirus 3 Jun 14. US Centers for Disease Control and Prevention. Department of Health and Human Services. 
  • Steckelberg, MD, James M. "Viral Gastroenteritis (stomach flu)". Diseases and Conditions 6 Mar 12. Mayo Foundation for Medical Education and Research.