Norovirus Worldwide

Global Trends

Worldwide, about one out of every five cases of acute gastroenteritis (inflammation of the stomach or intestines) that leads to diarrhea and vomiting is caused by norovirus. Norovirus causes 685 million cases of acute gastroenteritis, making it the most common cause of acute gastroenteritis worldwide. About 200 million cases are among children under 5, leading to an estimated 50,000 child deaths every year, mostly in developing countries. However, norovirus illness is a problem in both low and high income countries. Every year norovirus is estimated to cost $60 billion worldwide due to healthcare costs and lost productivity.

Norovirus illnesses and outbreaks worldwide are usually more common in cooler winter months. About half of all cases occur from December through February in countries above the equator, and in June through August in countries below the equator. However, in places closer to the equator, norovirus may be less seasonal.

Outbreaks

Worldwide, norovirus is the leading cause of acute gastroenteritis outbreaks. Since 2002, GII.4 strains (genogroup II genotype 4) have caused the majority of norovirus outbreaks worldwide. Although in recent years, non-GII.4 strains, such as GII.17 and GII.2, have replaced GII.4 strains in several Asian countries. New GII.4 strains emerge about every 2 to 4 years. Often, but not always, these new strains lead to an increase in norovirus outbreaks worldwide.

The CDC works with many global partners to identify the burden of acute gastroenteritis caused by norovirus and to prevent norovirus outbreaks.

Resources

• Estimates of the Global Burden of Foodborne DiseasesExternal
  This PLOS collection reports the first estimates of the incidence, mortality, and disease burden caused by 31 foodborne hazards
• The Global Burden of Norovirus & Prospects for Vaccine DevelopmentExternal
  This PLOS norovirus collection fills critical knowledge gaps and provides key information for the development of a much-needed vaccine. This is a “living collection” and more articles will be added over time.

• Global Burden of Norovirus and Prospects for Vaccine Development Cdc-pdf[4.39 MB, 46 pages]
  This report describes the work of norovirus researchers from around the world on the global burden of norovirus, and outlines further research needed to fill gaps in knowledge in order to make norovirus vaccines a reality.