1 of 8
Norovirus, also known as the "winter vomiting bug," is highly contagious. It can spread quickly through cruise ships, turning dream vacations into nightmares, or in other close quarters, such as schools, day care centers, and nursing homes. It can make you miserable for days—and there’s no vaccine.
Exposure to as few as 18 virus particles can make you sick, says William Schaffner, MD, professor in both the department of health policy and the division of infectious diseases at Vanderbilt University in Nashville, Tennessee. The number of norovirus particles that could fit on the head of a pin would be enough to infect more than 1,000 people, according to the Centers for Disease Control and Prevention (CDC). Norovirus causes between 19 and 21 million cases of vomiting and diarrheal illness, called acute gastroenteritis, in the U.S. each year.
Since there are many different norovirus types, it can infect you more than once. Outbreaks in the United States are most common from November to April, though you can become ill at any time.
Sources: Centers for Disease Control and Preventi... + 11
- Centers for Disease Control and Prevention. Norovirus. Page last reviewed May 4, 2022.
- Lopman, B. Global Burden of Norovirus and Prospects for Vaccine Development. Centers for Disease Control and Prevention. August 2015.
- William Schaffner, MD (professor of preventive medicine and professor of medicine) interview with the author, February 9, 2018.
- Centers for Disease Control and Prevention. When Evacuation is a Must – Protect Yourself from Norovirus. February 18, 2021.
- Centers for Disease Control and Prevention. Burden of Norovirus Illness in the U.S. Page last reviewed March 5, 2021.
- Centers for Disease Control and Prevention. About Norovirus. Page last reviewed March 5, 2021.
- Centers for Disease Control and Prevention. The Symptoms of Norovirus. Page last reviewed March 5, 2021.
- Centers for Disease Control and Prevention. Food Poisoning Symptoms. Page last reviewed December 7, 2022.
- Centers for Disease Control and Prevention. How Norovirus Spreads. Page last reviewed March 5, 2021.
- Centers for Disease Control and Prevention. Preventing Norovirus. Page last reviewed November 28, 2022.
- Centers for Disease Control and Prevention. Norovirus Illness: Key Facts. Page last updated January 2015.
- Centers for Disease Control and Prevention. Cleaning and Disinfecting With Bleach. Page last reviewed October 31, 2022.
