title: Direct and indirect effects of rotavirus vaccination upon childhood hospitalizations in 3 US Counties, 2006-2009.
abstract: BACKGROUND
  Routine rotavirus vaccination of US infants began in 2006. We conducted active, population-based surveillance for rotavirus gastroenteritis hospitalizations in 3 US counties to assess vaccine impact.
  
  
  METHODS
  Children <36 months old hospitalized with diarrhea and/or vomiting were enrolled from January through June each year during the period 2006-2009 and tested for rotavirus. Age-stratified rates of hospitalization for rotavirus infection were compared with corresponding vaccination coverage among a control group of children with acute respiratory illness. To assess direct and indirect benefits, vaccination coverage rates in the control group were multiplied by vaccine effectiveness estimates to calculate expected reductions in the rate of hospitalization for rotavirus infection. Rotavirus serotypes were compared across years.
  
  
  RESULTS
  Compared with 2006, a significant reduction in rates of hospitalization for rotavirus infection (P < .001) was observed in 2008 among all age groups. There was an 87% reduction in the 6-11-month-old age group (coverage, 77%), a 96% reduction in the 12-23-months-old age group (coverage, 46%), and a 92% reduction in the 24-35-month-old age group (coverage, 1%), which exceeded reductions expected on the basis of coverage and vaccine effectiveness estimates. Age-specific rate reductions were nearly equivalent to those expected on the basis of age-specific vaccine coverage in 2009. Predominant strains varied annually: G1P[8] (91%) in 2006; G1P[8] (45%) and G12P[8] (36%) in 2007; G1P[8] (89%) in 2008; and G3P[8] (43%), G2P[4] (34%), and G9P[8] (27%) in 2009.
  
  
  CONCLUSIONS
  Rotavirus vaccination has dramatically decreased rates of hospitalization for rotavirus infection among children in these US counties. In 2008, reductions were prominent among both vaccine-eligible age groups and older, largely unvaccinated children; the latter likely resulted from indirect protection. Although rates among age groups eligible for vaccination remained low in 2009, indirect benefits disappeared.
authors.affiliation: Epidemiology Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. dvp6@cdc.gov
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Payne
authors.forename: Mary Allen
authors.initials: MA
authors.lastname: Staat
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Edwards
authors.forename: Peter G
authors.initials: PG
authors.lastname: Szilagyi
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: Aaron T
authors.initials: AT
authors.lastname: Curns
authors.forename: Mary
authors.initials: M
authors.lastname: Wikswo
authors.forename: Jacqueline E
authors.initials: JE
authors.lastname: Tate
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Lopman
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
mesh_terms: D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology / Q000517:prevention & control; D005759:Gastroenteritis / Q000453:epidemiology* / Q000517:prevention & control*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D014481:United States / Q000453:epidemiology
chemical_list: D022243:Rotavirus Vaccines