Updated on June 21, 2024.
When a new school year begins, it’s time to get ready for the “stomach flu.”
This illness has nothing to do with influenza (the flu). The flu affects your nose, throat, and lungs. The stomach flu affects your digestive system. It’s made up of your stomach and intestines, or the tubes in your belly that food passes through.
The stomach flu can be caused by many different germs. In most cases, it’s caused by a virus called norovirus.
Norovirus affects about 20 million people in the United States each year. It sends about half a million people to the emergency room. These are mostly young children.
Norovirus is highly contagious, which means it spreads easily. But there are steps you can take to help lower your risk of getting it. Here’s what you should know.
How norovirus spreads
Anyone can get norovirus. It’s very easy for infected people to spread the virus to others.
Here’s how it can happen: Billions of pieces of norovirus can be found in poop. You could become infected if that poop gets into your mouth. This happens when an infected person doesn’t wash their hands after using the toilet. Then, they touch something with dirty hands.
Any object or food touched by an infected person can get norovirus on it. The foods where it appears most often include:
- Leafy greens
- Fresh fruits
- Oysters and other shellfish
If a person is sick and throwing up, they can also spread norovirus through the air.
People at higher risk for norovirus
People get the virus more often in colder months. That’s because they go indoors. The virus spreads easier in closed spaces with a lot of people.
But anyone who is living in a crowded, shared space is at higher risk. These spaces may include:
- College dorms
- Camps
- Hotels and cruise ships
- Community centers
- Childcare centers
People with weak immune systems may also be at higher risk. This includes people with cancer and HIV. It also includes people who take certain medicines, like steroids.
Symptoms of norovirus
People usually start to have symptoms a day or two after being exposed. These symptoms may include the following.
- Nausea
- Stomach cramping
- Vomiting
- Diarrhea, or loose and watery poop
- Headaches
- Muscle aches
- A low fever
Symptoms last for about 48 to 72 hours. People often recover fast. That means they get very sick then suddenly start feeling better.
Dehydration can be a more serious symptom of norovirus. That’s when your body doesn’t get the fluids it needs to work right. Norovirus makes it hard to keep fluids in your body. Symptoms include:
- Dry mouth
- Dry and wrinkled skin
- Dark yellow or orange pee
- Feeling dull, dizzy, or lightheaded
Young kids may seem to be crying but no tears come out. Babies or toddlers may have fewer wet diapers. They may also be very sleepy or fussy.
You should also look out for other serious symptoms. These include:
- Blood in your vomit or poop
- Intense belly pain
- A fever higher than 103 degrees
- Symptoms that last longer than one week
Seek medical help right away if you think you’re dehydrated or have any of these.
Treatments for norovirus
There is no “cure” for norovirus. It has to run its course. But there are steps you can take to help you feel better.
Stay hydrated. Take small sips of water or sports drinks. You don't have to drink a full glass at a time. Take a few sips and then 30 minutes later take another few sips. Avoid soda and fruit juice since the sugar in them can make diarrhea worse. If you have young children, keep an oral hydration solution like Pedialyte on hand.
Talk to a healthcare provider (HCP) if you’re dehydrated and can't drink anything without throwing up. You may need IV fluids, which are given through your veins. Or you may need medicine.
Talk to an HCP about medicine. They may give you a prescription drug to ease your symptoms. Don’t buy medicine at a drugstore without talking to an HCP first. If you don’t have norovirus, using the wrong drug can make things worse.
Eat as needed. There is no real proof that eating bland foods like bananas and toast will help you feel better. If you're getting hungry, eat what you think your stomach can handle.
How to lower your risk for infection
The best way to protect yourself is to wash your hands. Use soap and warm water and clean for at least 20 seconds. Hand sanitizer doesn’t kill norovirus, so stick to soap and water.
These steps can also help keep you healthy.
- Rinse off all fresh fruits and vegetables before you eat them.
- Cook shellfish all the way through.
- Don’t share plates, cups, or utensils with a sick person.
- Clean surfaces you touch often, like counters and doorknobs. Use a household cleaner with bleach or another product made to kill germs.
Stay home when you’re sick and a few days after you start feeling better. Even if your symptoms improve, you can still infect other people. Don’t return to school or work for another 48 to 72 hours.
