Norovirus notoriously easy to spread, difficult to kill


Dear Doctors: When my family tried to visit my parents at their assisted living facility, we were turned away at the door. I thought COVID-19 was going to be the reason, but we were told it was because of a norovirus outbreak. What is that? Is it really so contagious?

Dear Reader: Norovirus refers to a group of viruses that are the leading cause of gastrointestinal illness in the United States. They sicken 21 million people each year and send more than 100,000 of them to the hospital. Each year, these viruses cause 900 deaths, the majority of them in adults 65 and older.

Norovirus, which is shed in an infected person’s feces, is extremely contagious. If someone with norovirus fails to thoroughly wash their hands after a bowel movement, they can spread it to everything that they touch. You can become infected if you accidentally ingest the miniscule particles of feces that an infected individual leaves behind on a surface. This can be through person-to-person contact, consuming food or drink that they prepared or coming into contact with objects or surfaces that they have touched. The virus is present in vomit, as well, which adds an additional layer of risk when caring for or living with someone who is ill. To make things even more complicated, some people infected with norovirus don’t become sick, but they can still pass the virus to others.

Symptoms of norovirus infection begin from 12 hours to two days after exposure and often appear suddenly. The most common symptoms include nausea, repeated vomiting, stomach cramps and fatigue. Less often, someone may experience headache, low-grade fever, muscle aches and chills. While a miserable experience -- the infection has earned the nickname “the vomiting bug” -- it’s usually not life-threatening. But in vulnerable populations, such as infants, young children, older adults and those with a weakened immune system, infection can be severe.

Elizabeth Ko, MD and Eve Glazier, MD

Lab tests can detect noroviruses in a stool sample, but diagnosis is typically through the distinctive array of symptoms. There is no cure for this infection. Rather, the focus is on rest, managing discomfort, staying hydrated and meticulous hygiene to stop the spread. For those with a healthy immune system, recovery usually takes several days.

Because there are multiple means of transmission and the viral “dose” needed to cause an infection is so low, norovirus outbreaks are notoriously difficult to control. It’s particularly true in group settings such as hospitals, schools, cruise ships, nursing homes and assisted living facilities. Once an outbreak takes hold, it requires time and ongoing vigilance to eradicate. This includes repeatedly disinfecting every surface that may have been contaminated, and ensuring that everyone in the household or facility follows a strict regimen of frequent and thorough handwashing. Disposable gloves and paper towels should be used to clean up after a sick person, and they should be bagged before going into the trash. Infected people should stay home and avoid contact with others. While not getting to see your parents is disappointing, the no-visiting policy is quite likely part of the facility’s efforts to limit contact and control the outbreak.

The experts and specialists of UCLA Health Digestive Diseases offer consultations and care for all types of gastroenterological concerns. Learn more and schedule an appointment.

(Send your questions to [email protected], 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.)