Risk factors

Gastroenteritis occurs all over the world, affecting people of every age, race and background.

People who may be more susceptible to gastroenteritis include:

• Young children. Children in child care centers or elementary schools may be especially vulnerable because it takes time for a child's immune system to mature.
• Older adults. Adult immune systems tend to become less efficient later in life. Older adults in nursing homes, in particular, are vulnerable because their immune systems weaken and they live in close contact with others who may pass along germs.
• Schoolchildren, churchgoers or dormitory residents. Anywhere that groups of people come together in close quarters can be an environment for an intestinal infection to get passed.
• Anyone with a weakened immune system. If your resistance to infection is low — for instance, if your immune system is compromised by HIV/AIDS, chemotherapy or another medical condition — you may be especially at risk.

Each gastrointestinal virus has a season when it's most active. If you live in the Northern Hemisphere, for instance, you're more likely to have rotavirus or norovirus infections between October and April.