About Norovirus

Norovirus is a very contagious virus that causes vomiting and diarrhea. People of all ages can get infected and sick with norovirus.

Based on electron microscopic (EM) imagery, this three-dimensional (3D) illustration provides a graphical representation of a single norovirus virion, set against a white background.

Norovirus spreads easily!

People with norovirus illness can shed billions of norovirus particles. And only a few virus particles can make other people sick.

You can get norovirus from:
  • Having direct contact with an infected person
  • Consuming contaminated food or water
  • Touching contaminated surfaces and then putting your unwashed hands in your mouth

You can get norovirus illness many times in your life because there are many different types of noroviruses. Infection with one type of norovirus may not protect you against other types. It is possible to develop immunity to (protection against) specific types. But, it is not known exactly how long immunity lasts. This may explain why so many people of all ages get infected during norovirus outbreaks. Also, whether you are susceptible to norovirus infection is also determined in part by your genes.

Page last reviewed: October 5, 2015