The CDC says a new strain of norovirus now makes up a majority of outbreaks and that could be why it's spreading so quickly.

Norovirus, the highly contagious stomach bug that causes vomiting and diarrhea, is spiking across the US. What to know about ...

"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 ...