Norovirus: What is it? How does it spread?
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.
Anyone can get infected or sick from the norovirus. On average, one infected person will infect 2-7 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:
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- 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.
- Food that comes into contact with contaminated water.
- Touching surfaces or objects contaminated with norovirus and then putting your fingers in your mouth.
- 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.
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“6 in 10 infections are through direct contact, like shaking hands or touching door handles and then putting your hand in your mouth.” (CDC)
About one in every 15 individuals in the US will get norovirus illness annually. By five years of age, 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:
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- Young children (under the age of 5 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 also known as nursing homes (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 5 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)