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Norovirus Worldwide

Español: Norovirus en el mundo

Global Trends

Worldwide, norovirus is the leading cause of acute gastroenteritis (inflammation of the stomach or intestines or both). About 1 in 5 cases of acute gastroenteritis, which leads to diarrhea and vomiting, is caused by norovirus.

Norovirus is more often the cause of acute gastroenteritis among people in developed countries. In developed countries, norovirus causes about 1 in 5 cases of acute gastroenteritis; in developing countries, it’s about 1 in 6 cases. Overall, developing countries have more cases of acute gastroenteritis caused by different pathogens, such as viruses and bacteria. So, norovirus accounts for smaller fraction of all cases in these countries.

Norovirus Collection


The Global Burden of Norovirus & Prospects for Vaccine Development

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.

New Report Available

Global Burden report.

Global Burden of Norovirus and Prospects for Vaccine Development [4.39 MB, 46 pages] brings together the work of norovirus researchers from around the world to describe the burden of norovirus globally and outline further research needed to fill gaps in knowledge in order to make norovirus vaccines a reality.

With the widespread use of rotavirus vaccine, norovirus has surpassed rotavirus as the most common cause of acute gastroenteritis for which children need medical care in some countries, like the United States and Nicaragua. This trend is likely to continue as other countries routinely vaccinate against rotavirus.

Norovirus infections and outbreaks are usually more common in cooler, winter months. About half of all cases occur from December through February in countries above the equator (center line of the earth) and June through August in countries below the equator. However, in places closer to the equator, norovirus may be less seasonal. This may be because of temperature or the timing of the rainy season, but may also be related to when and how many babies are born.


Worldwide, norovirus is the leading cause of gastroenteritis outbreaks. The most common norovirus strain (genogroup II genotype 4) is a major cause of outbreaks worldwide. New norovirus strains emerge about every 2 to 4 years. Often, but not always, these new strains lead to an increase in outbreaks worldwide.

The CDC’s Division of Viral Diseases works with many global partners to identify the burden of acute gastroenteritis caused by norovirus and to prevent norovirus outbreaks throughout the world.

Learn more about norovirus


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