Dear Doctors: I got sick with a stomach bug, and it was so bad that my girlfriend insisted on me going to our local urgent care. They said I had norovirus. It lasted for three days, and it was miserable. Where does norovirus come from, and how can you avoid getting it?
Dear Reader: Being sick with any kind of stomach bug is deeply unpleasant. That said, norovirus is a notoriously nasty one. The symptoms come on suddenly, are typically quite severe and can cause the person to become dehydrated and weakened. This is particularly true in vulnerable populations, such as young children, older adults and people already weakened by chronic illness, surgery or medical treatments. Norovirus is highly contagious, easily transmissible and very difficult to eradicate. That means outbreaks are often seen in communal settings such as schools, restaurants, cruise ships, hospitals and nursing homes.
Norovirus is shed in an infected person’s vomit and stool. There is also evidence that the virus can be transmitted through saliva. You can become infected if you ingest as few as 10 viral particles. This can occur through contact with food, beverages, infected eating or cooking utensils, any surfaces an infected person touched, and with the infected person themselves. Anyone who is sickened by norovirus who fails to thoroughly wash their hands after using the bathroom can easily and widely transmit the illness.
The most common symptoms of illness include nausea, stomach cramps and severe and repeated vomiting and diarrhea. It is possible, but less common, for norovirus to cause a low-grade fever, chills, headache and body aches. Symptoms can begin from 12 hours to two days after initial contact with the virus. The person is infectious from the moment that symptoms begin, and for at least several days after they end. There is no medication for the illness. Treatment consists of rest, supportive care and plenty of fluids to replenish those lost during active symptoms.
In the United States, more than 2,500 norovirus outbreaks are reported each year, sickening more than 20 million people a year and causing 100,000 hospitalizations. It leads to about 900 deaths, mostly in older adults. According to the most recent data available from the Centers for Disease Control and Prevention, the U.S. saw 91 confirmed norovirus outbreaks in the first week of December 2024 alone. That’s more than double the number during the same week in the previous three years.
When a norovirus outbreak occurs, it takes time and ongoing vigilance to eradicate it. That means repeatedly disinfecting all of the items and surfaces that may have been contaminated by an infected person’s touch, or the aerosols of their vomit. (Yes, kind of gross, but important to know.) Repeated and thorough handwashing by everyone sharing a space with someone who is sick is crucial to staying healthy. Use disposable gloves and paper towels to clean up after the infected person, and immediately bag them and place them in the trash. Because the virus can be present in aerosols like sneezes and coughs, consider wearing a mask. Anyone sick with norovirus should stay home to avoid spreading the virus and infecting others.
(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
