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,

Ah, the classic signs of winter: Freezing temperatures, icy roads and empty tissue boxes. It's no secret that winter is a time when illness is prominent. Coughs, colds, and viruses are seemingly running rampant this time of year. This is thanks to the drier air and an influx of time spent indoors, according to the Mayo Clinic.

Norovirus cases are on the rise this winter. According to the CDC, there were a record 91 norovirus outbreaks reported by state health officials the week of December 5, 2024 (the most recent report)—the highest of the year.

The most common symptoms of norovirus are diarrhea, vomiting, nausea, and stomach pain. The virus may also cause body aches, fever and headaches, according to the CDC.

Norovirus, also known as the stomach bug, is spreading across the U.S. Here's what to know about the contagious virus and how best to prevent an infection.