News: 5 Gross Ways You Can Catch Norovirus, aka the Winter Vomiting Bug

It takes as little as 18 norovirus particles on your food to make you sick.

1 / 8

Norovirus, also known as the ''winter vomiting bug," is highly contagious. It often spreads quickly through cruise ships, turning dream vacations into nightmares, or in other close quarters, such as the Olympic Games, schools, day care centers and nursing homes. It can make you miserable for days—and there's no vaccine.

Exposure to as few as 18 virus particles can make you sick, says William Schaffner, MD, professor of preventive medicine at Vanderbilt University School of Medicine and a spokesperson for the Infectious Diseases Society of America. The amount of norovirus particles that could fit on the head of a pin would be enough to infect more than 1,000 people, according to the Centers for Disease Control and Prevention (CDC). Norovirus causes about 21 million cases of sickness, called acute gastroenteritis, in the US each year.

Since there are many different norovirus types, it can infect you more than once. While you can get it at any time, outbreaks in the US are most common from November to April.

Here's the gross part: People become infected with norovirus after accidentally getting stool or vomit from an infected person into their mouth. This happens in a variety of ways. But before you can prevent infection, you need to know if you have it.

Medically reviewed in March 2020.

Is it norovirus?

2 / 8 Is it norovirus?

Norovirus is the main cause of food-related illness in the US. Symptoms of norovirus infection often come on suddenly, says Schaffner. They can occur in as little as 12 to 48 hours. It usually lasts anywhere from 24 to 72 hours.

Many cases of food poisoning are caused by food contaminated with the norovirus. But food poisoning can also be bacterial and stem from improper handling of food. Symptoms of both can be similar—including upset stomach and cramps, nausea, vomiting, diarrhea and fever—no matter the source of contamination. 

To avoid norovirus, learn the five ways you can become infected.


Contaminated foods

3 / 8 Contaminated foods

People can become infected with norovirus if stool from an infected person gets into their mouth. This can happen when an infected person doesn't practice good hygiene after using the toilet and touches food with either dirty hands, or hands that weren’t washed thoroughly. Any food served raw or handled by an infected person after it's cooked can become contaminated with norovirus. Other foods, such as oysters, fruits and vegetables (raw or prepackaged) may be contaminated at their source.

To reduce your risk, wash your food before you eat it. Don’t eat food, such as salads, if you see they were touched with the bare hands of service workers, and don’t share utensils or food with someone who you think has norovirus. Wash fruits and vegetables thoroughly and cook oysters and other seafood sufficiently. Noroviruses are resilient—they can live even if temperatures get to 140 degrees Fahrenheit, so use enough heat to kill any germs.

Person-to-person contact

4 / 8 Person-to-person contact

Norovirus can also be spread by person-to-person contact, such as touching, Schaffner says. Billions of the virus particles can be found in vomit and stool, which explains how easy the norovirus is to catch.

To reduce risk, avoid shaking hands, Schaffner says. A good alternative is the ''elbow bump.”  Unlike a fist bump, an elbow bump often guarantees both person's body parts will be covered by clothing. "Or stand back, bow and smile," he suggests.

Stay as far away from people who are sick as possible, Schaffner adds. If children are sick, keep them out of areas where food is handled and prepared. Wash your hands with soap and water often, especially before eating or preparing food, after using the bathroom and after changing diapers.

Dirty surfaces

5 / 8 Dirty surfaces

You can pick up enough virus particles from surfaces, such as countertops or bathroom faucets, to get sick with norovirus, says Schaffner. Norovirus can linger on surfaces and objects for days or weeks.

To reduce risk, cruise ship operators have become diligent about using disinfectants frequently to clean surfaces, Schaffner says. The rest of us should follow suit.

Put on rubber gloves and a mask before cleaning infected surfaces. Use a chlorine bleach solution made up of 5 to 25 tablespoons of household bleach per gallon of water. The virus is so tough it can survive even when surfaces are cleaned with some other commercial disinfectants.

Another person’s vomit or stool

6 / 8 Another person’s vomit or stool

Direct contact with an infected person's vomit or stool—including from changing diapers—can also spread norovirus.

If surfaces are contaminated with vomit or stool from an infected person, wear gloves and clean and disinfect as soon as possible. Use the same chlorine bleach solution mentioned earlier.

Washing your hands can reduce risk of transmission. Using warm or cold water, lather your hands with soap. Scrub, rinse and air dry or dry with a clean towel. Hand sanitizers can help, but aren't as effective as handwashing. If you do use hand sanitizer, rub both sides of your hands and in between nails. Buy a brand that is at least 60 percent alcohol.

Bedsheets and clothes

7 / 8 Bedsheets and clothes

Bed linens and clothes contaminated with the vomit or stool of an infected person can spread norovirus.

Put on rubber or disposable gloves. Then, carefully launder the items in hot water, without agitating. Use the maximum length of the washing cycle on your machine. Then machine dry your linens and clothing.

Wash your hands thoroughly afterwards, especially if they came into contact with the linens and clothes.

Can it be treated?

8 / 8 Can it be treated?

There's no specific medicine or treatment for norovirus infection. "A major concern is dehydration," Schaffner says. It's important to stay hydrated and replace lost fluids—so drink plenty of water.

If your dehydration is mild, drinking sports drinks and other drinks without caffeine or alcohol can help, according to the CDC. Another option: buy an over-the-counter oral rehydration fluid. If your dehydration is severe, get medical help. Some symptoms might include urinating less frequently, and having a dry mouth and throat, as well as feeling dizzy when you stand up. Children who are dehydrated may be very sleepy or fussy, or may cry with few or no tears evident.

The infection can make you feel awful, but the good news—it's usually short-lived. "You feel miserable for about three days and then you feel better,” says Schaffner. However, even after you feel better, the virus can stay in your stool for two weeks or more. Continue practicing good hygiene such as thorough hand washing. And don't prepare food for others for at least two days after your symptoms go away.

Continue Learning about Viral Infections

What You Need to Know About Eastern Equine Encephalitis
What You Need to Know About Eastern Equine Encephalitis
From time to time, an illness called Eastern equine encephalitis (EEE) pops up in the news. In July 2019, for instance, the Florida Department of Heal...
Read More
What are adenoviruses?
Honor Society of Nursing (STTI)Honor Society of Nursing (STTI)
Adenoviruses are a group of viruses that cause respiratory tract and eye infections. Adenoviruses us...
More Answers
What is antigenic shift?
Anthony L. Komaroff, MDAnthony L. Komaroff, MD
The virus known as influenza is a quick-change artist that eludes the human immune response by m...
More Answers
What Time of Year Do Most Viral Infections Occur?
What Time of Year Do Most Viral Infections Occur?