Norovirus is Now the Leading Cause of Severe Gastroenteritis in U.S. Children

Norovirus is now the leading cause of acute gastroenteritis among children less than 5 years of age who seek medical care, according to a new study published in the New England Journal of Medicine.  Norovirus was responsible for nearly 1 million pediatric medical care visits for 2009 and 2010 in the United States, amounting to hundreds of millions of dollars in treatment costs each year.

Infants and young children are very susceptible to norovirus infections, which often result in a high risk of getting dehydrated from the sudden onset of intense vomiting and severe diarrhea, says Dr. Daniel Payne, an epidemiologist in the Division of Viral Diseases at the Centers for Disease Control and Prevention. Our study estimates that 1 in 278 U.S. children will be hospitalized for norovirus illness by the time they turn 5 years of age. It is also estimated that about 1 in 14 children will visit an emergency room and 1 in 6 will receive outpatient care for norovirus infections.

The researchers tracked infants and young children requiring medical care for acute gastroenteritis, which causes inflammation of the stomach and intestines, from October 2008 through September 2010. The study looked at more than 141,000 children less than 5 years of age living in three U.S. counties. Lab testing was done to confirm specimens for norovirus.

Norovirus was detected in 21 percent (278) of the 1,295 cases of acute gastroenteritis, while rotavirus was identified in only 12 percent (152) of the cases. About 50 percent of the medical care visits due to norovirus infections were among children aged 6 to 18 months. Infants and 1-year-old children were more likely to be hospitalized than older children. However, overall rates of norovirus in emergency rooms and outpatient offices were 20 to 40 times higher than hospitalization rates. Nationally, the researchers estimated that in 2009 and 2010, there were 14,000 hospitalizations, 281,000 emergency room visits, and 627,000 outpatient visits due to norovirus illness in children less than 5 years of age. This amounted to an estimated $273 million in treatment costs each year.

Our study confirmed that medical visits for rotavirus illness have decreased, says Payne. Also, our study reinforces the success of the U.S. rotavirus vaccination program and also emphasize the value of specific interventions to protect against norovirus illness. Norovirus vaccines are currently being developed, which may be especially important for young children and elderly people who are high risk.

Norovirus is highly contagious. Each year, more than 21 million people in the United States get infected with norovirus and develop acute gastroenteritis, and approximately 800 people die. Young children and elderly people are more likely to suffer from severe norovirus infections. The virus spreads primarily through close contact with infected people, such as caring for someone who is ill. It also spreads through contaminated food, water and hard surfaces. The best ways to reduce the risk of norovirus infection are through proper hand washing, safe food handling, and good hygiene.

For more information about norovirus, visit CDCs norovirus Web site at www.cdc.gov/norovirus.