Most outbreaks of norovirus illnesshappen when infected people spread the virus to others through direct contact, such as by caring for them or sharing food or eating utensils with them. Food, water, and surfaces contaminated with norovirus can also cause outbreaks.
Norovirus outbreaks have been reported in many settings. Some of the most commonly reported outbreak settings are listed below.
Healthcare Facilities
The most commonly reported setting for norovirus outbreaks in the United States and other industrialized countries is healthcare facilities, including long-term care facilities and hospitals. Over half of all norovirus outbreaks reported in the United States occur in long-term care facilities.
The virus can be introduced into healthcare facilities by infected patients, staff, visitors, or contaminated foods. Outbreaks in these settings can sometimes last months. Norovirus illnesses can be more severe and occasionally even deadly in patients in hospitals or long-term care facilities when compared with healthy people.
Restaurants and at Catered Events
Norovirus is the leading cause of outbreaks from contaminated food in the United States. About 50% of all outbreaks of food-related illness are caused by norovirus. Most of these outbreaks occur in food service settings like restaurants. Infected food workers are frequently the source of outbreaks in food-service settings, often by touching ready-to-eat foods, such as raw fruits and vegetables, with their bare hands before serving them. However, any food served raw or handled after being cooked can get contaminated with norovirus.
Norovirus outbreaks can also occur from food that is contaminated at the source or on the farm, such as oysters harvested from contaminated water, or fruit and vegetables sprayed with contaminated water in the field.
Foods that are commonly involved in norovirus outbreaks include:
- Leafy greens (such as lettuce)
- Fresh fruits
- Shellfish (such as oysters)
Schools and Childcare Centers
Norovirus outbreaks also frequently occur in schools, childcare centers, colleges, and universities. Norovirus outbreaks on school and university campuses have even led to campus closures. Close quarters, shared spaces, and high-touch surfaces make it easy for norovirus to spread in schools.
Cruise Ships
Norovirus is the most frequent (over 90%) cause of outbreaks of diarrheal disease on cruise ships and these outbreaks often get media attention, which is why some people call norovirus the “cruise ship virus.” However, norovirus outbreaks on cruise ships account for only a small percentage (1%) 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. When the ship docks, norovirus can be brought on board in contaminated food or water or by passengers who were infected while ashore. Repeated outbreaks on consecutive cruises may also result from infected crew or environmental contamination. This is because norovirus can persist on surfaces for days or weeks and is resistant to many common disinfectants.
FAQs
Most outbreaks of norovirus illness happen when infected people spread the virus to others through direct contact, such as by caring for them or sharing food or eating utensils with them. Food, water, and surfaces contaminated with norovirus can also cause outbreaks.
What is the setting for the most norovirus outbreaks? ›
Aside from health care facilities, the most common setting for a norovirus outbreak is a restaurant or catered event.
Where is norovirus most commonly found? ›
Contaminated Food and Water
Norovirus is the most common bug spread through food. People can get sick after they eat at restaurants where cooks or servers don't wash their hands before they touch your food. You can also get norovirus from raw foods like fruits and veggies grown with water that has infected poop.
Why is norovirus associated with outbreaks in institutional settings? ›
Because the virus can be transmitted by food, water, and contaminated environmental surfaces as well as directly from person to person, and because there is no long lasting immunity to norovirus, outbreaks can occur in a variety of institutional settings (e.g., nursing homes, hospitals, and schools) and affect people ...
What conditions does norovirus thrive in? ›
Norovirus can spread quickly in enclosed places like daycare centers, nursing homes, schools, and cruise ships. Norovirus can stay on objects and surfaces and still infect people for days or weeks. Norovirus can survive some disinfectants, making it hard to get rid of.
Why does norovirus peak in the winter? ›
We hypothesize that the reservoir may be maintained through the discharge of wastewater containing virus particles; wintertime seasonality may be explained by enhanced viral persistence at low temperatures.
Why is norovirus more common in the winter? ›
Moreover, the viruses can spread quickly, especially in places where people are in proximity, such as cruise ships, restaurant, and airline flights. Norovirus has a higher prevalence during winter months when people are most likely indoors – thus, the term “winter-vomiting bug.”
How do norovirus outbreaks start? ›
Norovirus is very contagious and spreads very easily and quickly in different ways. You can get norovirus by accidentally getting tiny particles of feces (poop) or vomit in your mouth from a person infected with norovirus.
When is the peak of norovirus season? ›
The CDC reports about 2,500 norovirus outbreaks in the U.S. every year. Outbreaks tend to occur between November and April but in years when there's a new viral strain, there can be up to 50% more illness. Norovirus causes over 100,000 hospitalizations and 900 deaths annually, mostly affecting adults 65 and older.
How to avoid catching norovirus? ›
To avoid catching norovirus or passing it on to others wash your hands frequently and thoroughly with soap and warm water. This is most important following an episode of illness, after using the toilet, before eating or preparing food, as well as cleaning up vomit or diarrhoea.
Norovirus outbreaks occur throughout the year but are most common from November to April. Most outbreaks occur when infected people spread the virus to others through direct contact, such as by caring for them or sharing food or eating utensils with them. Learn about common settings of norovirus outbreaks.
What populations are most at risk for norovirus? ›
But in some people — especially young children; older adults; and people with weakened immune systems or other medical conditions or who are pregnant — norovirus infection can be severe. Norovirus infection can cause severe dehydration and even death.
Is norovirus going around 2024? ›
Respiratory virus season may winding down as the U.S. enters spring, but the 2023–2024 norovirus season is still underway. Nationally, norovirus is circulating at the highest levels since last April, according to data from the U.S. Centers for Disease Control and Prevention.
Is norovirus killed by cooking? ›
Noroviruses are relatively resistant to heat and can survive temperatures as high as 145°F. Quick steaming processes may not heat foods enough to kill noroviruses. Food that might be contaminated with norovirus should be thrown out.
Who is less likely to get norovirus? ›
People with B blood type tend to be more resistant as fewer strains have evolved to attach to those particular oligosaccharides, whereas those with A, AB or O blood types are far more likely to become sick.
What kills norovirus? ›
In a plastic bucket, mix 5 to 25 tablespoons of household bleach in a gallon of water. This solution is great at killing norovirus, but becomes less potent if it is exposed to a lot of organic matter (such as vomit or stool).
Why are norovirus outbreaks associated with people in close proximity? ›
Infected people can spread norovirus to others through close contact or by contaminating food and surfaces. Food service workers who have norovirus can contaminate food and make many people sick.
How does norovirus spread in schools? ›
When an infected person vomits, norovirus can be sprayed into the air and contaminate nearby surfaces. Contamination of surfaces with fecal matter from unwashed hands can also occur. Norovirus can spread easily from person to person, through contaminated food or water, or by touching contaminated surfaces.
How does norovirus spread by contaminated environment? ›
Noroviruses are easily spread in environments where people are in close contact, and outbreaks often occur in group settings such as schools, hospitals, child care facilities and nursing homes.
What is norovirus outbreaks? ›
A norovirus outbreak is defined as an occurrence of two or more similar illnesses resulting from a common exposure that is either suspected or laboratory-confirmed to be caused by norovirus.
