Evidence from a new study points to norovirus as the leading cause of severe gastroenteritis in preschool-aged children.
Nearly 1 million children aged younger than 5 years sought medical treatment in 2009 and 2010 for acute gastroenteritis attributed to norovirus. This estimate was derived from data for 141,000 infants and young children in 3 US counties that were used to identify acute gastroenteritis from October 2008 through September 2010. Lab testing was performed on fecal specimens to confirm norovirus.
Findings showed norovirus in 21% (278) of 1,295 cases of acute gastroenteritis in contrast to rotavirus, detected in only 12% (152). Fifty percent of medical visits for norovirus infections were among children aged 6 months to 18 months. Infants and 1-year-olds were more likely to be hospitalized than older children. Overall, rates of norovirus in emergency departments (EDs) and outpatient offices were 20 times to 40 times higher than hospitalization rates.
Researchers estimate that in 2009 and 2010 there were 14,000 hospitalizations, 281,000 ED visits, and 627,000 outpatient visits among preschoolers attributed to norovirus, at an estimated treatment cost of $273 million each year. They extrapolate that 1 in 278 US children will be hospitalized, 1 in 14 will visit an ED, and 1 in 6 will receive outpatient care for norovirus illness by the time they are aged 5 years.
Norovirus inflames the lining of the stomach and intestines, causing severe vomiting and diarrhea. Infants, young children, and the elderly are especially susceptible and at high risk of dehydration. The illness is highly contagious and spread by close contact with infected persons or by contaminated food or water. Norovirus causes approximately 800 deaths each year, according to the Centers for Disease Control and Prevention.
Researchers suggest that the surge in norovirus cases among preschoolers may be because vaccination for rotavirus has resulted in better control of that illness. A norovirus vaccine is under development.