title: Norovirus and medically attended gastroenteritis in U.S. children.
abstract: BACKGROUND
  Cases of rotavirus-associated acute gastroenteritis have declined since the introduction of rotavirus vaccines, but the burden of norovirus-associated acute gastroenteritis in children remains to be assessed.
  
  
  METHODS
  We conducted active surveillance for laboratory-confirmed cases of norovirus among children younger than 5 years of age with acute gastroenteritis in hospitals, emergency departments, and outpatient clinical settings. The children resided in one of three U.S. counties during the years 2009 and 2010. Fecal specimens were tested for norovirus and rotavirus. We calculated population-based rates of norovirus-associated acute gastroenteritis and reviewed billing records to determine medical costs; these data were extrapolated to the U.S. population of children younger than 5 years of age.
  
  
  RESULTS
  Norovirus was detected in 21% of young children (278 of 1295) seeking medical attention for acute gastroenteritis in 2009 and 2010, with norovirus detected in 22% (165 of 742) in 2009 and 20% (113 of 553) in 2010 (P=0.43). The virus was also detected in 4% of healthy controls (19 of 493) in 2009. Rotavirus was identified in 12% of children with acute gastroenteritis (152 of 1295) in 2009 and 2010. The respective rates of hospitalization, emergency department visits, and outpatient visits for the norovirus were 8.6, 146.7, and 367.7 per 10,000 children younger than 5 years of age in 2009 and 5.8, 134.3, and 260.1 per 10,000 in 2010, with an estimated cost per episode of $3,918, $435, and $151, respectively, in 2009. Nationally, we estimate that the average numbers of annual hospitalizations, emergency department visits, and outpatient visits due to norovirus infection in 2009 and 2010 among U.S. children in this age group exceeded 14,000, 281,000, and 627,000, respectively, with more than $273 million in treatment costs each year.
  
  
  CONCLUSIONS
  Since the introduction of rotavirus vaccines, norovirus has become the leading cause of medically attended acute gastroenteritis in U.S. children and is associated with nearly 1 million health care visits annually. (Funded by the Centers for Disease Control and Prevention.).
authors.affiliation: Epidemiology Branch, Division of Viral Diseases, National Center for Immunizations and Respiratory Disease, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. dvp6@cdc.gov
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Payne
authors.forename: Jan
authors.initials: J
authors.lastname: Vinjé
authors.forename: Peter G
authors.initials: PG
authors.lastname: Szilagyi
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Edwards
authors.forename: Mary Allen
authors.initials: MA
authors.lastname: Staat
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Weinberg
authors.forename: Caroline B
authors.initials: CB
authors.lastname: Hall
authors.forename: James
authors.initials: J
authors.lastname: Chappell
authors.forename: David I
authors.initials: DI
authors.lastname: Bernstein
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Curns
authors.forename: Mary
authors.initials: M
authors.lastname: Wikswo
authors.forename: S Hannah
authors.initials: SH
authors.lastname: Shirley
authors.forename: Aron J
authors.initials: AJ
authors.lastname: Hall
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lopman
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
mesh_terms: D000208:Acute Disease; D000553:Ambulatory Care / Q000706:statistics & numerical data; D017250:Caliciviridae Infections / Q000191:economics / Q000453:epidemiology*; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D005759:Gastroenteritis / Q000821:virology*; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D008297:Male; D029322:Norovirus / Q000302:isolation & purification*; D011159:Population Surveillance; D011446:Prospective Studies; D012401:Rotavirus / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000453:epidemiology; D014481:United States / Q000453:epidemiology