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Norovirus: Preventing the highly contagious bug

January 14, 2025 | UCI Health
a man sitting on his sofa in front of the kitchen wearing a colorful blanket looking miserable holding his stomach

Norovirus, a highly contagious foodborne gastrointestinal disease, is on the rise this winter in California and the nation.

One reason, says Dr. Shruti Gohil, associate medical director of epidemiology and infection prevention at UCI Medical Center in Orange, is that we’re gathering in public and in large groups more than ever since the COVID-19 pandemic. Another is that we’ve become less vigilant about disinfection and hand hygiene.

"We've got more outbreaks, people are unmasked, people are engaging with each other, they're not cleaning their hands," she says. "This might be an indication that cleaning and disinfection are down post-COVID-19. We need to bring those practices back."

Often described as the stomach flu, norovirus requires serious precautions to keep it from spreading because the virus can survive on surfaces such as countertops, door knobs and elevator buttons for weeks.

“It is one of the most common forms of transmissible gastroenteritis — inflammation of the stomach and intestines — and is one of the most contagious viruses around.”

Stay away from others until healthy

“If you think you might have norovirus, be sure to keep others safe by keeping your hands and the surfaces you touch clean, and minimize physical contact with others until you have recovered,” she says.

But if you or a loved one are experiencing lightheadedness, dizziness or severe headache, seek immediate medical attention because it could be a sign of life-threatening dehydration.

According to the Centers for Disease Control and Prevention (CDC), more than 20 million cases of gastroenteritis caused by norovirus are reported annually. It is responsible for 58% of food-related illness.

Common symptoms include:

  • Diarrhea
  • Vomiting
  • Nausea
  • Stomach pain
  • Fever
  • Headache
  • Body aches

Hydration is crucial

Gohil says one of the most important things during a bout of norovirus is to stay hydrated as best as you can.

“Dehydration can quickly become life-threatening if it’s not addressed.”

An early warning sign of dehydration is headache. If one experiences dizziness or lightheadedness, she recommends going to the nearest emergency room.

Gohil says to watch for signs of dehydration in those who can’t communicate, such as babies and nonverbal individuals, including:

  • Inability to form tears
  • Dry mouth (lack of saliva)
  • Despondence
  • Slowed responsiveness

Recovering from norovirus

People usually develop symptoms 12 to 48 hours after being exposed to norovirus. Most of them get better within one to three days.

“Until then, drinking lots of fluids and keeping up your electrolytes will help support your recovery,” Gohil says.

Preventing the spread

People with norovirus are most contagious while experiencing symptoms and for a few days after they feel better. But studies show people can continue to shed the virus for at least two weeks after recovery, especially those with weakened immune systems.

The CDC suggests the following steps to help prevent the spread of norovirus:

Practice proper hand hygiene

  • Wash your hands carefully with soap and water — especially after using the toilet and changing diapers, and always before eating, preparing or handling food.
  • Note that hand sanitizer alone is not effective against norovirus.
  • Do not share food, drinks or utensils.
  • Noroviruses can be found in your vomit or stool (feces) even before you start feeling sick. Because the virus can stay in your stool for up to two weeks or longer after you feel better, it is important to continue these prevention practices through your contagious period.

Preparing food

  • Carefully wash fruits and vegetables before preparing and eating them. Cook oysters and other shellfish thoroughly before eating them.
  • Noroviruses are relatively hardy. They can withstand temperatures from below freezing to as high as 140°F. They can also survive quick steaming processes that are often used to cook shellfish.
  • Food that might be contaminated with norovirus should be thrown out.
  • Keep sick infants and children out of areas where food is being handled and prepared.
  • Do not prepare food for others or provide healthcare while you are sick and for at least two days after symptoms stop. This also applies to sick workers in settings such as schools and daycare facilities where they could expose people to norovirus.

Disinfect contaminated surfaces

  • After vomiting or having diarrhea, immediately clean and disinfect contaminated surfaces.
  • Use a chlorine bleach solution with a concentration of 1000–5000 ppm (5–25 tablespoons of household bleach per gallon of water) or other disinfectant the Environmental Protection Agency has registered [PDF] as effective against norovirus.

Wash laundry thoroughly

  • Immediately remove and wash clothes or linens that may be contaminated with vomit or stool, handling the soiled items without agitating them. 
  • Wear disposable gloves while handling soiled items and wash your hands afterward.
  • Wash soiled items with detergent in hot water at the maximum available cycle length, then machine dry them on high.

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