Cases ofnorovirus, a highly contagious stomach bug, have surged this winter. Nearly 1,000 cruise passengers on multiple ships got sick from a gastrointestinal illness outbreak after setting sail in December, according to the Centers for Disease Control and Prevention (CDC).Most of these outbreaks were attributed to norovirus.

The CDC also reported 91 norovirus cases during the week of Dec. 5, which was about three times the number reported two weeks prior and higher than the same week in recent years.

“Norovirus infections can occur at any time of year, but they tend to peak during the colder winter months—that happens every year. It is important to note that we do not know yet with certainty why we are seeing more norovirus outbreaks reported this year compared to previous years,”Jose Lucar, MD, an associate professor of medicine in the Division of Infectious Diseases at the George Washington University School of Medicine and Health Sciences, told Verywell in an email.

The rise in cases could stem from factors such as improved access to clinical diagnostic tests, more state health departments reporting norovirus data to the CDC, or a continued increase in post-pandemic gatherings. However, it’s unclear if the current norovirus strain has a better ability to spread between people, Lucar added.

Norovirus strains do evolve over time, which “can affect disease burden and potential disease severity,” and a new dominant strain typically emerges every three years, said Gabriel Alvarado, a CDC spokesperson.

Alcohol-based hand sanitizers don’t work well against the virus, so it’s important to wash your hands thoroughly with soap and warm water.It’s difficult to deactivate norovirus, and the virus can live on surfaces for a long time, saidStuart Ray, MD, a professor of medicine at the Johns Hopkins University School of Medicine.

“That’s one of the reasons this is such a nightmare for cruise ships because they really have to do intense cleaning of every surface,” Ray told Verywell.

Shigella vs. Norovirus: What’s the Difference Between These ‘Stomach Bugs’?

‘Violent’ Vomiting Is a Common Symptom

People usually develop severe vomiting and diarrhea within 12 to 48 hours of norovirus exposure, often resulting in dehydration.

“As it is violent and it starts suddenly, it also is very short-lived, or self-limited, and most people will get better within 48 hours,”Luis Ostrosky, MD, chief of infectious diseases with UTHealth Houston, told Verywell.

In some cases, people may also have fever, headaches, chills, and body aches. Vulnerable populations, like young children, older adults, and immunocompromised people, are at a greater risk for serious complications.

Reach out to a healthcare provider if you have any concerns, especially if your symptoms last longer than 48 hours, you have a high fever, or you notice blood in your stool, as these signs might mean you have a different infection, Ostrosky said.

What Are the Symptoms of Norovirus and How Long Do They Last?

Handwashing Is Key to Preventing Norovirus Spread

Since hand sanitizers don’t work well against norovirus, it’s essential to practice good hand-washing strategies. Ray said to wash your hands with warm water and soap for at least 10 seconds.

“It’s not a bad idea to isolate yourself when you’re really sick, because you don’t want to spread to others. It is very directly transmissible from person [to person], especially when you’re vomiting,” he added.

If you’ve had a norovirus infection in the past, you still need to take precautions against a future infection.

“Unfortunately, there are multiple types of norovirus, and they don’t provide immunity to each other, and infection with norovirus doesn’t provide lifelong immunity,” Ray said.

Norovirus also spreads through foods and drinks, especially if an infected person touches the item or it is placed on a contaminated surface. Water can also become contaminated if it is not treated properly or if someone vomits directly into the source.

Growingoystersor watering plants with contaminated water contributes to the spread of foodborne norovirus infections.To avoid this, it is important to wash fruits and vegetables and cook shellfish to at least 145°F. And, after recovering from a norovirus infection, you should wait at least 48 hours before preparing food to lower the risk of spreading the virus.

A Verywell Report: These Foods Are the Biggest Culprits of Foodborne Illness

Drink Liquids To Recover

There are no medications or vaccines for norovirus. Most people start feeling better after a few days, but staying hydrated is key. Instead of using sports drinks, it’s best to try over-the-counter oral rehydration fluids to replace the nutrients lost from vomiting and diarrhea.

“Some people may find relief taking over the counter medications such as bismuth subsalicylate for nausea and diarrhea. If symptoms become severe, some people may require emergency care, including the need for intravenous fluids and anti-nausea medication,” Lucar said.

To prevent the spread, it’s a good idea to stay home for 48 hours even after you feel better and stop having symptoms.

“For all age groups, people should seek medical attention if symptoms worsen, last for several days, or they can’t keep fluids down,” Lucar said.

Differences Between Norovirus and Food Poisoning

What This Means For YouMost people with norovirus recover after a few days, but reach out to a healthcare provider if your symptoms last for over 48 hours or if you have a persistent high fever. Norovirus is very contagious, so take precautions like proper handwashing to reduce the chance of spreading the illness.

What This Means For You

Most people with norovirus recover after a few days, but reach out to a healthcare provider if your symptoms last for over 48 hours or if you have a persistent high fever. Norovirus is very contagious, so take precautions like proper handwashing to reduce the chance of spreading the illness.

7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Outbreaks on cruise ships in VSP’s jurisdiction.Centers for Disease Control and Prevention.NoroSTAT data table.Centers for Disease Control and Prevention.About norovirus.Centers for Disease Control and Prevention.How to prevent norovirus.Minnesota Department of Health.Norovirus fact sheet.Centers for Disease Control and Prevention.How norovirus spreads.Centers for Disease Control and Prevention.How to prevent norovirus.

7 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Outbreaks on cruise ships in VSP’s jurisdiction.Centers for Disease Control and Prevention.NoroSTAT data table.Centers for Disease Control and Prevention.About norovirus.Centers for Disease Control and Prevention.How to prevent norovirus.Minnesota Department of Health.Norovirus fact sheet.Centers for Disease Control and Prevention.How norovirus spreads.Centers for Disease Control and Prevention.How to prevent norovirus.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Centers for Disease Control and Prevention.Outbreaks on cruise ships in VSP’s jurisdiction.Centers for Disease Control and Prevention.NoroSTAT data table.Centers for Disease Control and Prevention.About norovirus.Centers for Disease Control and Prevention.How to prevent norovirus.Minnesota Department of Health.Norovirus fact sheet.Centers for Disease Control and Prevention.How norovirus spreads.Centers for Disease Control and Prevention.How to prevent norovirus.

Centers for Disease Control and Prevention.Outbreaks on cruise ships in VSP’s jurisdiction.

Centers for Disease Control and Prevention.NoroSTAT data table.

Centers for Disease Control and Prevention.About norovirus.

Centers for Disease Control and Prevention.How to prevent norovirus.

Minnesota Department of Health.Norovirus fact sheet.

Centers for Disease Control and Prevention.How norovirus spreads.

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