Winter is not only a time when respiratory viruses like the flu and RSV flourish, it is also the season for severe gastrointestinal illness caused by the highly contagious norovirus.
CDC tracking from 14 states shows that 91 outbreaks were recorded in the beginning of December 2024, which is more than double the maximum average reported for the same week during the previous three years. The most recent count is also a jump from the week prior, when 69 outbreaks were tallied by state health departments.
“We’re seeing a ton of vomiting and diarrhea right now because of norovirus,” says Erica Prochaska, MD, a pediatric infectious diseases specialist with Johns Hopkins Children’s Center in Baltimore. “This stomach virus typically becomes more common during the winter months when people are inside and close to each other, and we’re seeing it surge more now compared to other years.”
Norovirus Is Often Transmitted Through Food
Food workers are a common source of virus spread as they may touch ready-to-eat foods (such as raw fruits and vegetables) before serving them. They can also spread illness by handling any kind of food (raw or cooked), utensils, or surfaces, or by touching other people.
“Norovirus can persist for fairly long times on inanimate surfaces like a stair railing, doorknobs, and other objects like that,” says Dean Winslow, MD, an infectious-disease specialist and a professor of medicine at Stanford University in California.
Restaurants, Schools, and Cruises Are Norovirus Hot Spots
Because contaminated food is a major source of norovirus, restaurants and catered events are common settings for outbreaks.
Dr. Winslow attributes the rise in cases in part to people interacting, traveling, and gathering together more following the isolated and more cautious times of the COVID-19 pandemic.
“People are back out there living their lives, going to bars, restaurants, and on cruises, and this may be a factor in the spread of norovirus,” he says.
Symptoms of Norovirus Can Come on Quickly
“Compared to many of the other viruses that cause gastrointestinal infections, norovirus causes prominent nausea and vomiting during the first day of illness — even more prominent than the diarrhea,” says Winslow.
How to Stop Norovirus Spread
- Wash your hands well. Use soap and water for at least 20 seconds, especially after using the toilet or changing diapers; before eating, preparing, or handling food; and before giving yourself or someone else medicine. “The virus does not wash off of hands with sanitizer very well — it really requires a good scrub with soap and water,” says Dr. Prochaska.
- If sick, do not prepare food or care for others. Wait at least two days (48 hours) after symptoms stop. Studies, however, have shown that you can still spread norovirus for two weeks or more after you feel better.
- Clean and disinfect surfaces and wash clothes. The virus can survive on practically any surface — in some cases, up to 12 hours on hard surfaces and up to 12 days on carpet. Disinfecting can help.
In the weeks ahead, Prochaska encourages the public to keep up with preventive practices.
“I think we’re still in the thick of things,” she says. “We typically see a lot of transmission through the colder months, and then things let up in the early to mid spring.”
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