Norovirus Outbreaks: Doctors Warn Common Precaution Won't Prevent Illness

Amid a severe norovirus outbreak, the Centers for Disease Control and Prevention (CDC) and infectious disease experts are urging people to avoid relying on hand sanitizers and instead focus on handwashing with soap and water to prevent the virus from spreading further.

"Alcohol based hand cleansers are not effective to neutralize norovirus," Dr. Jatin Vyas, an infectious disease professor at Columbia University Medical School in New York City, told Newsweek in an email Friday.

Newsweek has reached out to several infectious disease experts for comment via email on Friday.

Why It Matters

The highly contagious illness has reached its highest levels for this time of year in more than a decade, according to the latest CDC data, but prevention measures could help reduce its spread.

The CDC has reported 91 outbreaks during the week of December 5, up from an average of 65 during the same period from 2012 to 2020.

As the illness causes an average of 900 deaths annually, mostly among older adults, along with 109,000 hospitalizations and 19 million to 21 million cases in the U.S. each year, prevention measures can be lifesaving.

What To Know

Dr. William Schaffner, an infectious disease professor at Vanderbilt University School of Medicine in Nashville, Tennessee, told Newsweek in an email on Friday that "Norovirus is hardy and rather resistant to pH and temperature changes as well as some disinfectants including alcohol which is the active ingredient in hand sanitizers and wipes."

He added, "on the other hand, soap and water work well, but may not be as readily available," as sanitizer which may be in people's bags or pockets.

Speaking on the science behind sanitizer's ineffectiveness, Vyas referred to a 2015 scientific paper in the peer-reviewed Journal of Hospital Infection, which found "Washing hands with soap and water is better than using alcohol-based hand disinfectants in removing noroviruses from hands."

Vyas told Newsweek that the effectiveness or ineffectiveness of hand sanitizer relates to the virus' makeup, saying: "Viruses that lack an envelope use a protein core (capsid) to protect them. Lipid bilayers (envelope) are sensitive to alcohol-based cleansers. Those viruses that lack envelope are more resistant to alcohol-based cleansers." Norovirus does not have a lipid bilayer, therefore making it more resistant to sanitizer.

A spokesperson for the CDC echoed this sentiment in a Friday email to Newsweek, explaining: "Soap and water work to remove germs from hands, while sanitizer acts by killing certain germs on the skin. Hand sanitizer's primary active ingredient is alcohol. Alcohol is ineffective against norovirus because the virus's protective protein shell, called a capsid, prevents the alcohol from penetrating and inactivating the virus."

Norovirus is the leading cause of foodborne illness in the U.S., responsible for nearly 58 percent of foodborne infections annually. A tiny dose of just 10 viral particles can make a person ill, making it one of the most easily transmissible pathogens.

The CDC has identified leafy vegetables, fresh fruits, and shellfish as a common source of norovirus outbreaks. The Food and Drug Administration (FDA) has issued its fourth oyster recall in three weeks, reflecting an alarming increase in norovirus outbreaks across the nation.

Given the virus is not sensitive to cold temperature and is relatively heat resistant, foods that could be contaminated should be cooked at temperatures higher than 145 degrees Fahrenheit.

Symptoms are often brief but intense, with infected individuals typically experiencing 24 to 48 hours of discomfort, beginning with nausea, vomiting, and followed by diarrhea, among other symptoms.

Most people recover within one to three days, with the exceptions of the elderly, immunocompromised people, and some children. Dehydration is a top concern for sensitive groups.

The majority of the illness is passed through contaminated food and fomites, inanimate objects or surfaces that a contaminated individual touched. The virus can stay on surfaces and objects for several hours, and the CDC encourages people to clean and disinfect surfaces.

In addition, the CDC recommends washing "hands well with soap and water; hand sanitizer alone does not work well against norovirus." Proper handwashing involves using soap and water for at least 20 seconds.

The CDC warns that "You can find norovirus in your vomit or feces (poop) even before you start feeling sick," and "the virus can also stay in your poop for 2 weeks or more after you feel better. You can still spread norovirus during that time."

What People Are Saying

The CDC said in a public health statement: "The rise in cases emphasizes the need for preventive measures. Early recognition of symptoms and isolating cases can limit further spread."

Holland America Line, a cruise charter that had two outbreaks, said in a statement: "We initiated enhanced sanitation protocols on both ships in conjunction with the [CDC] to minimize further transmission. As a further precaution, upon arrival in Fort Lauderdale ... both ships underwent additional and comprehensive sanitization before embarking on their next voyages with no further outbreaks."

Dr. Mark Loafman, assistant chair of Family and Community Medicine at Cook County Health, told NBC Chicago: "The norovirus doesn't get killed with hand sanitizer. So those alcohol products don't work...It's one of those times, especially if you have any symptoms, 20 seconds soap and warm water, scrubbing your hands before you leave the bathroom. It's really, really important."

What Happens Next

The CDC and doctors urge people to be cautious with potentially contaminated foods and to wash their hands regularly to help curb the rising number of norovirus cases across the U.S.

Update 1/4/2025, 9:15 a.m. ET: This article has been updated to include comment from the CDC.

Update 1/3/2025, 1:10 p.m. ET: This article has been updated to include comment from Dr. Vyas.