How long is stomach flu contagious cdc

Q: How long after stomach bug are you contagious?

Although you typically feel better after a day or two, youre contagious for a few days after you recover. The virus can remain in your stool for up to two weeks or more after recovery. Children should stay home from school or child care for at least 48 hours after the last time they vomit or have diarrhea.

What is norovirus?

Norovirus is a virus that causes illness of the same name. Norovirus illness is commonly called other names such as viral gastroenteritis, stomach flu, and food poisoning.
Norovirus infection causes acute gastroenteritis (inflammation of the stomach and intestines).
The most common symptoms are watery diarrhea, explosive projectile vomiting (that shoots out), and stomach pain.
Anyone can get norovirus, and can have the illness multiple times in their lifetime.
The sources of norovirus are people (specifically, the feces and vomit of infected individuals), as well as raw or undercooked shellfish.

How serious is a norovirus illness?

People with norovirus can feel extremely ill and experience vomiting or diarrhea many times a day.
Most people get better within 1 to 2 days.
Dehydration can be a problem among some people, especially the very young, the elderly, and people with other illnesses.

How contagious is norovirus?

Norovirus illness is highly contagious. As few as 10 viral particles can cause infection; the average stool or vomit volume can contain over 100 million particles.
People with norovirus are contagious from the moment they begin feeling ill to anywhere from 3 days to 2 weeks after they have recovered.
Norovirus can survive in the environment for long periods of time. It can survive freezing conditions and heat exposure up to 140°F.
Norovirus can spread rapidly in closed environments like dormitories, daycare centers, prisons, cruise ships, and nursing homes.

How is norovirus spread?

The virus is spread by contaminated individuals touching items or handling food, or through vomit or feces of infected individuals.
The illness is spread when people:
- Eat food or drink liquids that are contaminated with norovirus.
- Touch surfaces or objects that are contaminated with norovirus, and then place their hand in their mouth.
- Have direct contact with an infected person — such as caring for or sharing food, drinks, or eating utensils with an infected person.

How can I prevent the spread of norovirus?

Practice proper hand hygiene:
- Wash your hands carefully with soap and water, especially after using the toilet and changing diapers, and always before eating or preparing food.
- Alcohol-based hand sanitizers (containing at least 62% ethanol) may be a helpful addition to hand washing, but they are not a substitute for washing with soap and water. See CDC's Handwashing: Clean Hands Save Lives.
Take care in the kitchen.
- Carefully wash fruits and vegetables.
- Cook oysters and other shellfish thoroughly before eating them.
Don't prepare food while infected. People who are infected with norovirus should not prepare food for others while they have symptoms and for 3 days after they recover from their illness.
Wash laundry thoroughly.
- Immediately remove and wash clothing or linens that may be contaminated with vomit or fecal matter.
- Handle soiled items carefully, without agitating them, to avoid spreading virus.
- Wash items with detergent at the maximum available cycle length and then machine dry.
Clean and disinfect contaminated surfaces, especially after an episode of vomiting or diarrhea, with a solution of bleach and water. Some recommended strengths are:
- 1 tablespoon of bleach per gallon of water for stainless steel, food/mouth contact items, and toys.
- 1/3 cup of bleach per gallon of water for non-porous surfaces such as tile floors, counter-tops, sinks, and toilets.
- 1½ cups of bleach per gallon of water for pourous surfaces such as wooden floors.

Is there specific treatment or vaccine for norovirus?

There is no vaccine to prevent norovirus infection, although this is an area of active research.
There is no specific drug to treat people with norovirus illness.
Rehydration is important for infected people — they must drink plenty of liquids to replace fluid lost through vomiting and diarrhea. In some cases, fluids may need to be given intravenously.

More Resources

Norovirus in Shellfish
Foodborne Illnesses
Recreational Water Illnesses

For Public Health Partners

Report Norovirus related to Foodborne Disease Outbreak
Report Norovirus related to Waterborne Disease Outbreak

Table of Contents Show

What is norovirus?
How serious is a norovirus illness?
How contagious is norovirus?
How is norovirus spread?
How can I prevent the spread of norovirus?
Is there specific treatment or vaccine for norovirus?
More Resources
Dehydration in children
Duration in children
Younger children
How long after stomach bug are you contagious?
Is the stomach flu contagious through air?

Stomach flu is extremely contagious and can spread through person-to-person contact. A person can also catch it after coming into contact with contaminated water or food. Symptoms can pass within 3 days.

Stomach flu is one of several ways to refer to viral gastroenteritis.

Several viruses can cause viral gastroenteritis. According to one article, the most common virus in the United States to cause viral gastroenteritis is currently the norovirus. This accounts for 19–21 million cases per year.

In most cases, the illness is self-limiting and will clear within 1–3 days.

This article will explain how long stomach flu is contagious for and how long the symptoms can last. It will also explore the symptoms of stomach flu and when to contact a doctor and provide information on treatment and prevention methods.

Stomach flu is highly contagious.

According to the Centers for Disease Control and Prevention (CDC), a person with the norovirus is most contagious when they have symptoms of the illness, such as vomiting, and during the first few days after they have recovered.

However, they also state that a person can be contagious for up to 2 weeks following the infection.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) state that the norovirus can live on surfaces such as countertops for months.

Consuming contaminated food or water, coming into contact with bodily fluids from a person with the norovirus, and swimming in contaminated water are all ways to catch the virus.

If another virus is responsible for the infection, it may not clear up as quickly.

The NIDDK indicate the following time scales depending on the virus causing the infection:

Norovirus: Symptoms of this virus can last between 1 and 3 days.
Rotavirus: Symptoms of this virus can last between 3 and 8 days. However, it is less common in the U.S. due to vaccinations.
Astrovirus: Symptoms of this virus can last between 1 and 4 days.
Adenovirus: Symptoms of this virus can last between 1 and 2 weeks.

A person with the norovirus typically does not require treatment unless they become dehydrated.

However, they may need to go to the hospital if they do not receive proper care, and they:

are a young child
are an older adult
have a weakened immune system

The norovirus can survive on surfaces such as changing tables for months. A person can also catch the virus if they come into contact with bodily fluids, such as vomit or stools, from the child.

Symptoms

Common symptoms of stomach flu in children may include:

nausea
vomiting
watery diarrhea

Some other symptoms a child might experience include:

headache
fever
chills
stomachache

Dehydration in children

Parents or caregivers of children should look for the following symptoms or complaints from their children, as they can indicate dehydration.

Symptoms of dehydration in infants or children include:

less frequent urination or no wet diapers for 3 or more hours
thirst
dry mouth
lack of energy
sunken cheeks or eyes
no tears when crying
decreased skin turgor

Duration in children

Although children can vomit more than adults, vomiting can often stop in children after 24 hours.

If the vomiting increases after 24 hours, a parent or caregiver should contact a doctor.

If the vomiting does not stop but does not increase significantly, the parent or caregiver should try to give the child clear liquids. They should not rush trying to give the child heavier foods.

There are some steps a person can take to avoid catching stomach flu.

The most common route of infection is the fecal-oral route. In other words, most cases come from contact with infected stool.

The CDC add that a person can also catch the norovirus from:

contaminated foods
contaminated water
unclean surfaces

To help prevent getting stomach flu caused by the norovirus, the CDC recommend that people:

Avoid preparing foods for others when sick and for 2 days after the symptoms end.
Cook shellfish thoroughly.
Wash the hands frequently.
Rinse fruits and vegetables well.
Stay at home when sick and for 2 days after the symptoms end.

Learn more about how to prevent stomach flu here.

Some symptoms of stomach flu can suggest a severe case. They could also indicate dehydration or a different, potentially more serious, condition.

According to the NIDDK, a person should contact a doctor if they experience any of the following symptoms:

high fever
diarrhea lasting for longer than 2 days
black, tarry, or bloody stool
severe pain in the abdomen or rectum
vomiting frequently
six or more loose stools in a day
symptoms of dehydration

If a person notices a change in their or another adult or child’s mental state, including lack of energy or irritability, they should also contact a doctor.

A person should contact a doctor if their symptoms do not improve within a few days. It is possible that they have a different underlying condition.

One article recommends that people follow a bland diet when they have stomach flu and are recovering from its symptoms.

A person should also drink plenty of fluids containing electrolytes. These include low sugar sports drinks.

Read about 33 foods a person can eat with stomach flu here.

Younger children

Younger children can drink Pedialyte to consume fluid with electrolytes.

However, the NIDDK recommend avoiding drinks that contain excessive amounts of sugar, such as fruit juice and soda, since sugar can make diarrhea symptoms worse.

A common cause of stomach flu is the norovirus. However, other viruses, bacteria, parasites, and chemicals can also cause it to occur.

Stomach flu symptoms are mainly related to the digestive tract and can cause vomiting and diarrhea.

Symptoms of stomach flu can last between 1 day and 2 weeks, depending on the cause. Norovirus symptoms usually pass within 3 days. A person is contagious while they have symptoms.

A person should seek symptom relief within a few days and should use caution for several days following symptoms, since they may still be contagious at that point.

A person should contact a doctor if they experience any symptoms of dehydration or any worsening symptoms that do not clear or start to get better within a few days.

How long after stomach bug are you contagious?

Although you typically feel better after a day or two, you're contagious for a few days after you recover. The virus can remain in your stool for up to two weeks or more after recovery. Children should stay home from school or child care for at least 48 hours after the last time they vomit or have diarrhea.

Is the stomach flu contagious through air?

Another way to catch the stomach flu is by breathing in airborne viruses after an ill person vomits. If the illness is not quickly recognized and steps immediately taken to control it, the infection will spread rapidly from person to person.