The virus, often colloquially referred to as “stomach flu,” saw the percentage of positive tests double during the first week of January compared to last year. Positive test percentages for cases of norovirus in the United States are double what they were at the same period a year ago,

The U.S. is seeing a "quad-demic" as cases of COVID-19, flu, RSV and norovirus spread at the same time. Experts said this is what you need to know.

Rates of norovirus in that CDC system have reached levels at or above last season's peak in all regions of the country. Norovirus test positivity rates look to be the worst in the Midwest, in a grouping of states spanning Kansas through Michigan.

First came the fires. Then, there was ash and contaminated water. Now, some survivors of the Southern California wildfires are dealing with outbreaks of norovirus and other stomach ailments at a shelter set up to help evacuees.

"It is too early to tell if this strain is associated with more severe norovirus disease but likely lower population immunity is the reason for the early surge of an otherwise seasonal increase of this virus," Jan Vinjé, head of the CDC's CaliciNet system, told CBS News in an email.

As the norovirus cases continue to spread in the U.S., you can't rely on hand sanitizer alone to protect you, experts warn.Norovirus causes gastrointestinal symptoms like nausea, vomiting, diarrhea and stomach cramps.

You can also get norovirus by touching objects or surfaces that are contaminated and then putting your hands in your mouth without washing them first. Hand-washing with soap and water is key, as hand sanitizer will not do the trick in the case of norovirus, experts say.

Flu season is here in California, but other illnesses are in full swing in the Golden State. Here are the symptoms and how long you're contagious.

The cases mark the fourth norovirus outbreak on Holland America ships since early December, following others on its Eurodam, Rotterdam and Zuiderdam vessels. Other companies, including Cunard Line and Princess Cruises also saw outbreaks in recent weeks.

An outbreak of the norovirus has been reported at the Pasadena Evacuation Center, officials confirmed. The Pasadena Public Health Department said that three cases of the norovirus were confirmed

Multiple norovirus outbreaks have been reported in Chicago during the month of January, the Chicago Department of Public Health confirmed this week.

Meanwhile, for norovirus, 27.91% of weekly tests have come back positive during the same week, CDC data showed. This appears to be the highest levels seen since 2019. Doctors told ABC News that ...