Norovirus outbreaks are on the rise this winter. How to avoid the contagious stomach bug, symptoms to look out for and what to do if you catch it.
Norovirus is raging in the United States this winter. According to the latest data from the Centers for Disease Control and Prevention, there were 91 outbreaks reported by state health departments the week of Dec. 5, the most cases seen at this time of year since 2012.
That's concerning, given that norovirus, a stomach bug, is highly contagious. According to the CDC, it causes an average of 19 million illnesses, mostly in young children, annually in the country, and leads to 465,000 emergency department visits. With numbers on the rise already, we'll see what 2025 holds. Lowering your risk for getting norovirus is important, especially if you are in one of the vulnerable populations for this illness.
How can you prevent norovirus and what should you do if you get it? Here’s what experts want you to know.
Dr. Nipunie Rajapakse, a pediatric infectious diseases physician with the Mayo Clinic Children's Center, tells Yahoo Life that norovirus is unrelated to influenza, despite its nickname. Instead, norovirus is “a type of virus that causes gastroenteritis or ‘stomach flu.’”
“Norovirus is also known as the cruise ship virus because of its frequent outbreaks on cruise ships and military bases — and it's circulating everywhere,” Dr. Craig Wilen, associate professor in laboratory medicine and immunobiology at the Yale School of Medicine, tells Yahoo Life. “We have no drugs or vaccines for it, so it's a major public health burden.”
Unlike the flu, which often includes respiratory symptoms like a cough, gastroenteritis attacks your intestines, says Rajapakse, causing inflammation. This causes symptoms such as:
Nausea and vomiting are the two big signs that you have norovirus, and these symptoms typically last one to two days. One of the risks of these symptoms is dehydration, which is a concern if a person is not hydrating properly or keeping fluids down. This is particularly dangerous for young children, the elderly and those who are immunosuppressed, Wilen says.
If you have norovirus, there’s typically no reason to see a doctor unless you find yourself suffering from dehydration, signs of which include going to the bathroom less often, dry mouth and dizziness in adults, according to the CDC. “Fluids and electrolytes is what you need, as well as trying your best not to spread the illness to household contacts, which is more difficult than one might think,” Wilen says. Over-the-counter antidiarrheal medications can also help.
“We don’t have many tools in the toolbox to avoid spread, unfortunately," says Wilen, "but the good news is that most cases will clear up in a few days.”
Norovirus is "largely spread through the fecal-oral route,” Wilen explains. “Virus that’s either in the stool or in the vomit will either get on someone’s hands or a food product, and then get into the mouth or gastrointestinal tract of the recipient.”
Keeping your hands clean is key. While spraying your hands with sanitizer may be a go-to move since the pandemic started, it’s not going to do much when it comes to avoiding the norovirus, says Wilen. That’s because “the virus is relatively resistant to ethanol-based cleaners, like hand sanitizer,” he says. Instead, washing your hands with soap and warm water, particularly after using the bathroom or before preparing food, is your best move for avoiding transferring the virus from your hands. You should also make sure to avoid sharing any food with someone who may be infected.
In order to kill the virus on surfaces in the home, Wilen suggests using bleach-based cleaning products. Or you can make your own using a mixture of 5-25 tablespoons of household bleach to 1 gallon water, per the Mayo Clinic.
Also according to the Mayo Clinic, you can follow these tips to avoid spreading or catching norovirus:
A version of this story was originally published in February 2024.
Norovirus cases are surging in parts of the U.S. this winter, CDC data show
Cases of norovirus, a wretched and highly contagious stomach bug, are surging in parts of the United States this winter, according to government data.
The most recent numbers from the U.S. Centers for Disease Control and Prevention show there were 91 outbreaks of norovirus reported during the week of Dec. 5, up from 69 outbreaks the last week of November.
Numbers from the past few years show a maximum of 65 outbreaks reported during that first week of December.
A norovirus infection is characterized by sudden vomiting and diarrhea. Outbreaks are often seen on cruise ships, in congregate living situations like nursing homes and jails, as well as schools and places where people are close together. Earlier this month, hundreds of cruise passengers fell ill with norovirus on three different ships, according to the CDC, which recorded outbreaks of the virus on 14 cruises overall this year. December has so far seen the highest number of cruise ship outbreaks in the span of a month compared with any other month in 2024.
Cases are ticking up on land, too. The Minnesota Department of Health recently logged 40 cases of norovirus, which is twice the usual number for December, CBS News Minnesota reported.
Here are a few things to know about the virus.
Norovirus is the leading cause of foodborne illness in the United States, responsible for 58% of such infections acquired in the country each year, according to the CDC.
Dr. Leana Wen, the former health commissioner in Baltimore, shared some best practices for people to protect themselves against the disease on "Face the Nation with Margaret Brennan" Sunday.
"Wash your hands, really well, especially if you're going to buffets. Wash your hands if you're touching commonly touched surfaces, before you touch your mouth, before you touch your nose," said Wen. "Norovirus is the most common foodborne illness here in the U.S. It's very hard to avoid once it's in your family. And, also, don't prepare food if you're having vomiting, diarrhea, stomach cramps, because you don't want to spread it to other people."
Norovirus infections are caused by a group of viruses that spread easily, with as few as 10 viral particles having the ability to make someone sick, health experts say.
There are about 2,500 norovirus outbreaks reported annually in the United States. The outbreaks can occur throughout the year but are most common from November to April.
Along with vomiting and diarrhea, common symptoms include nausea, stomach pain, body aches, headache and fever.
Most norovirus outbreaks occur when people who are already infected spread the virus to others by direct means, such as through sharing food or eating utensils. Outbreaks can also be spread through food, water or contaminated surfaces.
Illness caused by norovirus typically starts suddenly, with symptoms developing 12 to 48 hours following exposure to the virus. Most people get better within one to three days and recover fully.
But with 19 to 21 million illnesses each year in the United States, norovirus nevertheless causes on average 900 deaths and 109,000 hospitalizations annually, mostly among adults aged 65 and older. It also leads to 465,000 emergency department visits, mostly involving young children.
People of all ages can get infected and fall sick from norovirus. Young children, older people and those with weakened immune systems are most at risk, with dehydration from vomiting and diarrhea the top concern.
There is no medication to treat norovirus. Rehydration is recommended by drinking water and other liquids, with the exception of coffee, tea and alcohol.
Anyone suffering from dehydration should seek medical help. Symptoms of dehydration include a decrease in urination, dry mouth and throat, and feeling dizzy when standing. Dehydrated children may be unusually sleepy or fussy and cry with few or no tears.
Rigorous and frequent handwashing is the best defense against norovirus during the peak winter season, scrubbing the hands with soap and warm water for 20 seconds before meals.
Scrubbing surfaces with household disinfectants can also help.
Norovirus outbreaks reported on 3 cruise ships this month, sickening hundreds
Hundreds of cruise passengers and workers fell ill with norovirus on three different ships this month, the Centers for Disease Control and Prevention said.
The CDC has logged outbreaks in 2024 on 14 cruise voyages, but three ships were hit in December. This is the only month this year when the CDC has reported three confirmed norovirus outbreaks on cruise ships and there's still more than a week to go before the month ends. In all, 301 passengers and crew members fell ill during the December outbreaks, health officials said.
Those on Princess Cruises' Ruby Princess, on a trip around Hawaii's island, and Holland America's Rotterdam and Zuiderdam voyages, both in the Caribbean, mostly dealt with diarrhea and vomiting.
The most recent outbreak was on Holland America's Rotterdam ship, which set sail on Dec. 8 and is set to end its Caribbeantrip Friday in Fort Lauderdale.
Officials said 83 of the 2,192 passengers on board and 12 of the 953 crew members were sickened.
"At Holland America Line, the safety and well-being of our guests and crew is our top priority. During the current voyage, a number of guests on Rotterdam reported symptoms of gastrointestinal illness," a Holland America spokesperson said. "The cases have mostly been mild and quickly resolving."
In response to the outbreak, there was additional cleaning and disinfection. Sick passengers and crew members were isolated. Stool specimens were collected for testing. The cruise line also consulted with the CDC's Vessel Sanitation Program.
Once the Rotterdam ship arrives in Fort Lauderdale on Friday, it will undergo a comprehensive sanitization process before its next trip, according to the cruise line.
There was also a norovirus outbreak on Holland America's Zuiderdam voyage earlier this month. Over the course of the Dec. 4-Dec. 11 voyage, 87 out of 1,923 passengers were reported ill, in addition to four of the 757 crew members, according to health officials.
A Holland America spokesperson declined to comment on the Zuiderdam outbreak because the voyage had already ended.
Princess Cruises also dealt with a norovirus outbreak this month on its Ruby Princess ship during a cruise that started on Dec. 2 and ended on Wednesday. The ship started its journey in San Francisco and toured around Hawaii, according to CruiseMapper.
In all, 103 of 3,001 passengers and 12 of 1,142 crew members onboard reported being ill.
The Ruby Princess was also subject to increased cleaning and disinfection procedures, according to the CDC. Stool specimens were collected for testing and sick passengers and crew members were isolated. The cruise line consulted with the CDC's Vessel Sanitation Program.
CBS News has reached out to Princess Cruises for comment.
There are about 2,500 reported norovirus outbreaks in the U.S. each year. Norovirus, which is sometimes called the "cruise ship virus," causes more than 90% of diarrheal disease outbreaks on cruise ships, according to the CDC. However, norovirus outbreaks on cruise ships account for only a small percentage of all reported norovirus outbreaks.
"Norovirus can be especially challenging to control on cruise ships because of the close living quarters, shared dining areas, and rapid turnover of passengers," according to the CDC. "When the ship docks, norovirus can be brought on board in contaminated food or water; or by passengers who were infected while ashore."
This year, the CDC has logged outbreaks on 14 cruise voyages. Norovirus was listed as the causative agent for most of the outbreaks, though one was caused by salmonella and one was caused by E. coli.The causative agent of one outbreak remains unknown.
Norovirus outbreaks are usually more common during cooler months, typically happening from November to April in countries above the equator, according to the CDC.
Norovirus Cases Are Up. Here’s How To Protect Against ‘Stomach Flu’
Outbreaks of highly contagious norovirus are up in the U.S. Also known as the "winter vomiting bug" or "stomach flu," the seasonal illness is at its highest recorded level this time of year for more than a decade.
Officials reported 91 suspected or confirmed norovirus outbreaks over the first week of December. This is the highest level seen at this time of year since at least 2012, and one of the highest case loads reported at any time of year over the last 12 years.
As this Centers for Disease Control and Prevention data only currently covers 14 states, it doesn't give a comprehensive picture of norovirus across the country. Increasing numbers of cases may be influenced by more states joining the program over the years.
Nonetheless, it reflects peaks and trends in the spread of the virus, which usually circulates more widely between November and April every year. The U.S. reports around 2,500 outbreaks a year, typically peaking in February.
This year, it appears its hitting harder, earlier, possibly as more people get together "for the first time in several years," experts told Fortune magazine.
Many countries are seeing an uptick in several seasonal viruses as people mingle more over the holidays than they did during the pandemic. Diseases like flu and respiratory illness RSV are all on the up and, although it doesn't represent the same threat it once did, COVID-19 is circulating widely. Relatively high levels of whooping cough, which can be deadly for infants, are also of concern to public health experts.
Countries like the U.K. have issued numerous public statements to encourage members of the public to get vaccinated against illnesses and practice everyday hygiene measures to prevent the spread of contagious diseases.
Officials in the country's public health system says they're battling a "quad-demic" of flu, COVID-19, RSV and norovirus, with 95% of England's hospital beds full by early December.
Norovirus is the most common cause of vomiting, diarrhea, and foodborne illness in the U.S. Although it's often referred to as "stomach flu," it's not related to influenza.
The virus spreads via tiny particles of infected fecal matter that enter the mouth. This means you can catch it by eating or drinking something contaminated with the virus and by touching your mouth after you've touched a contaminated surface like a doorknob. If you're looking after someone with the disease, it can be easy to catch it yourself.
Norovirus often causes vomiting, nausea, diarrhea and stomach pain, but may also result in fever, headaches and body aches. It can be very unpleasant, but most people will recover within about three days of developing symptoms.
It's important to drink water if you catch norovirus, as both vomiting and diarrhea can cause dehydration. If you suspect someone with norovirus has severe dehydration, seek medical help.
You can protect against norovirus with vigilant hand-washing. Regularly wash your hands with soap and warm water for at least 20 seconds, especially after using the bathroom, changing a baby's diaper, shaking someone's hand or caring for someone with the disease.
Don't share food or drinks with a person infected with the disease, and make sure to wash any potentially contaminated sheets and clothes in hot water.
Washing fruit and vegetables and cooking seafood thoroughly will help prevent the virus spreading through food.
If you catch norovirus, you can protect others by staying at home for two days after your symptoms stop. You can pass on the disease for two weeks after your symptoms resolve, so make sure to keep washing your hands regularly.
Unfortunately, there's currently no vaccine against norovirus. But researchers at Moderna are recently started trials of a candidate shot that may one day offer protection.
Vaccines are the best way to prevent against several other seasonal illnesses, as well as other diseases like whooping cough and measles that are on the rise in the U.S.
Flu vaccines are available every year during fall. They are recommended annually for almost everyone over the age of 6 months, and are especially important for people at risk of severe disease, which hospitalizes betwen 140,000 and 710,000 Americans — and tragically kills an estimated 12,000 to 51,000 — every year.
RSV vaccines are available for older people and pregnant people, who can confer protection on to their vulnerable infants.
COVID-19 vaccines are recommended annually for anyone aged 6 months or older. They are particularly important for older adults, people at risk of severe disease, and people who have never had a vaccine.
Full details of each vaccine are available on the CDC website.
