If you have norovirus, you probably won’t soon forget it—even though you’d like to. “Norovirus is an illness that causes diarrhea, often accompanied by nausea and vomiting,” explains Kimon Zachary, MD, a Mass General Brigham infectious diseases doctor. “For most people, it’s not dangerous, but it’s definitely unpleasant.”
Dr. Zachary shares the signs and symptoms of norovirus, how to prevent infection, and what to do if you get sick.
You’ve probably heard people talk about the “stomach flu.” In reality, the influenza (flu) virus is an infection of the respiratory (breathing) system, with symptoms such as cough, sore throat, and fever. Influenza sometimes causes an upset stomach in kids, but it’s not the virus that sends adults running to the bathroom.
What people really mean when they say “stomach flu” is usually viral gastroenteritis—an infection that causes inflammation in the lining of the stomach and intestines. Several different viruses can cause gastroenteritis. But norovirus is one of the most common culprits.
Symptoms of norovirus include:
Nausea and vomiting
Stomach pain and cramping
Other viruses that cause gastroenteritis are more likely to cause diarrhea alone, Dr. Zachary explains. Unfortunately for people with norovirus, this illness often causes diarrhea and vomiting. Still, some people can experience just one or the other. “There’s quite a variety in how sick people get with norovirus,” he says.
Blood in the stool is not usually a sign of norovirus, Dr. Zachary adds. If you experience that symptom, you should check in with your primary care provider. You may have another infection or other medical condition that requires different treatment.
Norovirus is released with an infected person’s stool and vomit. From there, it spreads easily to all sorts of surfaces in the bathroom and beyond. “It can get onto a person’s hands and contaminate any surface they touch or any food they prepare,” Dr. Zachary says. “And it’s a hardy virus that can survive on surfaces for hours — or even days.”
Norovirus outbreaks on cruise ships often make the news. But there’s nothing special about ships that make them a likely source of the virus, Dr. Zachary explains.
“Cruise ships are notorious for spreading viruses because there are a lot of people together in a closed setting, touching the same things, and often eating in close proximity or even in buffet-style dining,” he says. “But norovirus clusters can arise anywhere people are in close contact or sharing food, including office parties, picnics, barbecues, holiday gatherings, and other events.”
Because norovirus is so hardy, it can be a tricky germ to avoid. “It’s challenging to prevent,” Dr. Zachary notes. “Alcohol-based hand sanitizers aren’t very effective against this virus.”
Still, you can take steps to reduce the odds of catching norovirus. The most important thing to do is wash your hands often with soap and water for at least 20 seconds. That’s especially important if you’re spending time in close, crowded settings.
If you suspect someone in your household has norovirus, everyone in the house should wash hands often, Dr. Zachary adds. You should also clean any potentially contaminated surfaces with a cleaning product that contains bleach. “It’s hard to prevent spread within the household, but it’s worth a try,” he says.
If you’re infected with norovirus, you’ll know it soon. Most people experience symptoms within 12 to 24 hours of exposure. “It’s a pretty quick onset,” Dr. Zachary says.
Most people can manage the illness on their own at home. But it may be more severe in people who have other serious medical conditions. Diarrhea and vomiting can lead to dehydration, so norovirus can be particularly concerning for people who are vulnerable to dehydration, such as those with heart or kidney disease.
Even if you’re not medically vulnerable, it’s a good idea to check in with your primary care provider if you suspect you might have norovirus, Dr. Zachary says. “Your provider can review your symptoms with you and help you decide if further action is needed,” he adds.