Children who get infected may have severe watery diarrhea, often with vomiting, fever, and abdominal pain. Vomiting and watery diarrhea can last from 3 to 8 days.

Additional symptoms may include loss of appetite and dehydration (loss of body fluids), which can be especially dangerous for infants and young children. Symptoms of dehydration include decrease in urination, dry mouth and throat and feeling dizzy when standing up. Severe dehydration can lead to death in rare cases, so it is important to recognize and treat rotavirus infection immediately.

Usually a child's first time getting Rotavirus causes the most severe symptoms. However, vaccinated children are much less likely to get sick from Rotavirus, and if they do get sick, their symptoms are usually less severe than unvaccinated children.