The most common symptoms of norovirus are diarrhea, vomiting, nausea and stomach pain, according to the Centers for Disease Control and Prevention. The agency lists fever, headache and body aches as other symptoms. This page reports what the CDC states and is not personal medical advice.
When symptoms start and how long they last
| Question | What the CDC says |
|---|---|
| When symptoms start | Usually 12 to 48 hours after exposure |
| How long illness lasts | Most people get better within 1 to 3 days |
| How long a person can spread it | 2 weeks or more after feeling better |
The first two rows come from the CDC's About Norovirus page. The third comes from its page on how norovirus spreads, which also says a person is most contagious while having symptoms and during the few days after feeling better.
The CDC describes norovirus as a very contagious virus that causes acute gastroenteritis, an inflammation of the stomach or intestines. The agency says it is sometimes called the "stomach flu" or the "stomach bug" but is not related to the flu, which is caused by the influenza virus. For flu and other respiratory illness, see Is flu and respiratory illness high in my state?
Signs of dehydration
The CDC says a person with norovirus can vomit or have diarrhea many times a day, and that this can lead to dehydration, especially in young children, older adults and people with other illnesses. The agency lists these symptoms of dehydration:
- Decreased urination
- Dry mouth and throat
- Feeling dizzy when standing up
- In children, crying with few or no tears and unusual sleepiness or fussiness
The same page says there is no specific medicine to treat norovirus illness, and that antibiotics will not help because they fight bacteria, not viruses. The CDC's guidance is to drink plenty of liquids to replace fluid lost from vomiting and diarrhea. It says oral rehydration fluids sold over the counter are most helpful for mild dehydration, and that a person who thinks they or someone in their care is severely dehydrated should call a doctor.
How norovirus spreads
The CDC says norovirus spreads easily and quickly, and that a person can get it in different ways, including:
- Having direct contact with someone who has norovirus, such as caring for them, sharing food or eating utensils with them, or eating food they handled.
- Eating food or drinking liquids that are contaminated with norovirus.
- Touching contaminated objects or surfaces and then putting unwashed fingers in the mouth.
The agency's page on how the virus spreads says it takes only a few norovirus particles to make a person sick. Its prevention page says the virus can be found in vomit or feces even before a person starts feeling sick.
What the CDC says about prevention
The CDC's prevention page gives these steps:
- Wash hands often with soap and water for at least 20 seconds, especially after using the toilet or changing diapers and before eating, preparing or handling food. The agency says hand sanitizer does not work well against norovirus and is not a substitute for handwashing.
- Do not prepare or handle food or care for others while sick, and wait at least 2 days (48 hours) after symptoms stop.
- Wash fruits and vegetables well, and cook oysters and other shellfish thoroughly to an internal temperature of at least 145°F.
- After someone vomits or has diarrhea, clean and disinfect the entire area. The CDC says to use a chlorine bleach solution of 1,000 to 5,000 ppm, which it gives as 5 to 25 tablespoons of household bleach (5% to 8%) per gallon of water, or a disinfecting product registered with the Environmental Protection Agency against norovirus, and to leave bleach on the area for at least 5 minutes.
- Wash clothes or linens that may have vomit or feces on them with detergent and hot water at the maximum cycle length, then machine dry them at the highest heat setting.