A sharp increase in norovirus cases is sweeping the United States, according to the latest data from the Centers for Disease Control and Prevention (CDC). Often called the "stomach flu," norovirus is a leading cause of gastroenteritis,

Outbreaks of the highly contagious stomach virus are more than double what they were last year at the time, CDC says. Protect yourself by washing hands with soap often — antibacterial gel doesn't work well against the virus.

The CDC reported more than double the cases of norovirus, commonly known as stomach flu, compared to previous years in early December.