Norovirus: What is it? How does it spread?
Posted on 03/02/2023

What is Norovirus?
Norovirus is a very contagious virus commonly referred to as "food poisoning," the "stomach bug," or the "stomach flu." The norovirus infection causes gastroenteritis (inflammation of the stomach and intestines), which can lead to diarrhea, vomiting, stomach pain and sometimes fevers. 

Norovirus can happen year-round; however, the CDC reports a seasonal pattern, with norovirus happening in colder months and peaking between February and March. 

How does it spread? 
Anyone can get infected or sick from the norovirus. On average, one infected person will infect two to seven other people. (NCBI) Research also shows that you can spread the virus even if you don't have symptoms. 

Norovirus can live on surfaces for days and spreads by accidentally getting tiny pieces of feces (poop) or vomit from an infected person into someone's mouth. CDC reports it can spread by: 

  1. Eating food or drinking liquids that are contaminated with norovirus.
    •  This can happen when an infected person with viral particles on their hands touches food with their bare hands, after improper handwashing and/or without proper protection (including gloves, a mask or plastic apron).
    •  Or when tiny drops of vomit from an infected person spread through the air and land on food.
  2.  Food that comes into contact with contaminated water.
  3.  Touching surfaces or objects contaminated with norovirus and then putting your fingers in your mouth.
  4.  Having direct contact with someone infected with norovirus by caring for them, sharing food, sharing bedding, eating utensils with them or even through changing diapers.  

“Six in 10 infections are through direct contact, like shaking hands or touching door handles and then putting your hand in your mouth.” (CDC) 

Who is at risk? 
About one in every 15 individuals in the U.S. will get norovirus illness annually. Statistics show that by five years old, one out of every 14 children will visit an emergency room due to Norovirus. (NFID)

Anyone can get infected with norovirus; those at risk for more severe infections: 

  • Young children (under the age of five years).
  •  Older adults (85 years and older).
  •  People with weakened immune systems or those with medical conditions.
  •  People who are pregnant.  

Three out of four norovirus outbreaks occur in long-term care facilities (nursing homes), according to the CDC. Restaurants and schools are also prone to norovirus outbreaks due to poor hand washing with young people. Cruise ship outbreaks usually make the news but only account for 1% of outbreaks. Healthcare facilities and other institutional settings (e.g., daycare centers, schools, etc.) are particularly at-risk for outbreaks because of increased person-to-person contact. 

“Children under five years old and adults aged 85 years and older are more likely to have an outpatient or emergency department visit than people of other ages. Of those who die [due to norovirus or dehydration caused by the virus], 90% are persons aged 65 years and older.” (JAMA) 

How can you protect yourself and loved ones?
Handwashing is always best because hand sanitizer does not work well against norovirus. 

Wash your hands thoroughly for at least 20 seconds vigorously with soap and warm/hot water: 

  • After using the toilet or changing diapers.
  •  Before eating, preparing, or handling food.
  •  Before giving yourself or someone else medicine.
  •  After handling the bedding of someone who is ill. 

There is no vaccine, but most people get better within one to two days with no long-term health effects. The norovirus can be dangerous to people under five and over 65, but there are ways to protect yourself and those you love.  

Due to an "outer shell" called a capsid protecting the virus, it's hard to kill the norovirus. Only some chemicals can break through the "outer shell", so cleaning with the proper chemicals like bleach or other EPA-approved disinfectants are the best.  

Before you start mixing bleach and water for cleaning, first put on disposable plastic gloves, a mask, and if possible, a plastic apron to avoid contamination.  

  • Bleach
    •  Food Contact Surfaces & Toys:
      •  Add 1 Tablespoon of Bleach in 1 Gallon of Water. (1:250 ratio)
    •  Soiled Areas (covered in vomit or diarrhea):
      •  Isolate and block off contaminated areas from other people and pets. 
      •  Put on PPE (Personal Protective Equipment), disposable gloves, a mask and a plastic/disposable apron.
      •  Use disposable absorbent materials (paper towels, kitty litter, baking soda, etc..) to soak up or even scrape off (with a paper plate or carboard) vomit or stool. 
      •  Throw away everything used to clean up the mess, including gloves and food within a 25-foot circle near the vomit or diarrhea. Take this garbage out of the house immediately to prevent further transmission. 
      •  Wash hands, put on clean gloves and rinse the surface with soapy water and wipe the area dry. 
      •  Now it’s time to disinfect; add 1 and 2/3 cups of household bleach in 1 gallon of water. (1:10 ratio)
      •  Follow instructions on the container for “heavily contaminated areas.”
    • Non-Porous Surfaces (stainless steel, metal, glass, hard plastic and varnished wood):
      •  1/3 cup of household bleach in 1 gallon of water. (1:50 ratio)
  •  Non-Chlorine Bleach (EPA-Approved Disinfectants)
    •  Read the label carefully for specialized "disinfecting" instructions when sanitizing food surfaces or medical equipment.
    •  Steam clean carpets, upholstery, or other items that cannot be disinfected with bleach or chemical solution.
    •  Clothing should be washed in a laundry machine and dried on the hottest cycle available. 

For more information, see EPA's Registered Antimicrobial Products Effective Against Norovirus. 

What are the Symptoms and Treatment for Norovirus?

Symptoms of "stomach flu" include: 

  • Abdominal bloating or pain
  •  Body aches
  •  Fever and chills
  •  Headache
  •  Vomiting and nausea
  •  Watery diarrhea 

Signs of Dehydration (biggest risk with the stomach flu): 

  • Dark urine 
  • Dizziness 
  • Fatigue  
  • Lightheadedness 
  • Thirst 
  • Urinating less than normal 

Infants, children, and the elderly are most susceptible to dehydration: 

  • Dry mouth and tongue  
  • Irritability and listlessness  
  • No tears with crying 
  • No wet diapers for three hours 
  • Sunken cheeks, eyes, or soft spots

Seek immediate medical care for:  

  • Bloody vomit or diarrhea  
  • High fever 
  • Can't keep liquids down 
  • Severe abdominal pain 
  • Vomiting or diarrhea for

 What to do if you are sick with the “stomach flu” (norovirus): 

  • Drink plenty of liquids to replace fluids lost from vomiting and diarrhea, which will help prevent dehydration. (Water is important and even having a ginger ale for example can be a good way to get fluids and sometimes it can be calming for the GI tract.) 
  • If you get sick, the good news is that it only lasts 24-48 hours. But stay home at least two days after symptoms are gone. 
  • Use the longest dishwasher setting to kill the virus. Handwashing dishes are not enough because the water doesn't get hot enough to kill the virus. The virus can stick to plates and sticky substances like cheese. 
  • Consider clothes, blankets, and linens contaminated, so wash them in the laundry machine and dry them on the hottest cycle available.  
  • Clean high-touch surfaces, like doorknobs, thoroughly and often with the correct cleaning chemicals.

You can help share this information by downloading our 2023 BFHD "Protect Yourself Against Norovirus" Flyer:

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