If your child has a stomach bug, it could be norovirus—a highly contagious stomach virus that causes diarrhea and vomiting. Cases of this virus are on the rise in New York City and much of the northeastern United States, according to the Centers for Disease Control and Prevention.

While typically mild in older children and adults, lasting usually only a few days, norovirus can cause severe dehydration in babies and kids with certain underlying conditions. Knowing how to care for them is crucial.

In this Q&A, Tessa Scripps, MD, a pediatrician at the Mount Sinai Kravis Children’s Hospital, and Assistant Professor of Pediatrics at the Icahn School of Medicine and Mount Sinai, answers your questions about the disease, including what to do if your child is sick.

What is norovirus, and what are norovirus symptoms?

Norovirus is a common contagious virus that inflames the intestines, causing nausea, diarrhea, and throwing up. Sometimes it can also cause fever. The disease is spread when particles from an infected person’s feces or vomit spreads to others, typically in bathrooms, but also by eating or drinking contaminated foods and beverages; using contaminated utensils; touching contaminated surfaces; or having any direct contact with someone who is infected. Norovirus is highly transmissible, and infected people can actually shed billions of norovirus particles at a time, but it can take fewer than 100 norovirus particles to make another person sick. People are most contagious when they actively have symptoms and in the few days after their symptoms have resolved.

Tessa Scripps, MD

How can I protect my child from catching norovirus?

The most common way norovirus is spread is through close contact with an infected person, so it’s a good idea to keep kids some distance from people who are sick, or who have recently recovered from being sick. Norovirus can infect an entire family at the same time, since even simple contact with others can lead to infection. So, the most important thing is for kids to wash hands frequently with soap and warm water, and for adults to do the same, especially if any of you have been in contact with a person who has symptoms. Alcohol-based sanitizers do not work as effectively against preventing transmission.

My child has norovirus. How does their age or health condition affect their risk for severe illness?

Newborn babies and children who have underlying chronic illnesses such as kidney disease and diabetes are at higher risk for becoming dehydrated and severely ill because excessive fluid losses can affect their kidney and their liver function. It’s important they get medical attention right away if symptoms last longer than three days or if they’re unable to keep hydrated.

What symptoms might indicate my child needs medical help?

Watch for symptoms of dehydration, such as decreased or less frequent urination and small volume- or very dark or strong-smelling urine. If it has been more than eight hours from when your child has had a wet diaper or used the toilet to pee, reach out to your doctor for advice. A rapid heart rate or a significant change in your child’s activity can also be a sign of dehydration. If you notice that your child seems very lethargic and listless, you should seek medical advice right away.

What can I do to help my child recover from norovirus?

Once the virus has passed and the vomiting and diarrhea have subsided, make sure they are well hydrated and rested. For newborns and infants, you can give them small amounts of breast milk or formula. Toddlers, older children, and adults should drink small volumes of fluids—about one to two ounces every one to two hours—to ensure fluids get absorbed and to prevent recurrent vomiting. Drinking water and electrolyte fluids like Pedialyte^®, Gatorade, or watered down apple juice can be very useful to maintain hydration, and can help prevent complications from norovirus. They can also have bland foods like rice, dry cereal, applesauce, bananas, and crackers.

Are there any medications I can give my child to ease their norovirus symptoms?

There are no over-the-counter anti-diarrheals or anti-nausea medicines that are recommended for children. In rare cases, pediatricians may prescribe Zofran, an anti-emetic, to help children stop vomiting so they can re-hydrate without the need for intravenous fluids.

How do I prevent norovirus from spreading to my other kids?

It is important that everyone in your house washes their hands regularly with warm water, and avoid sharing food and drinking cups with anyone who is sick. You should also wipe down any contaminated surfaces with a bleach-based disinfectant, especially toilets and sinks after an infected child has used them. And everyone should try to maintain some distance from infected household members while they’re actively sick.

Is there a test for norovirus I can give my child?

Testing is available. However, norovirus is similar to other types of stomach infections, such as rotavirus, and symptom management is the same, so testing isn’t useful. If there has been an outbreak at your child’s school and they are sick, there is a good chance they have norovirus.