title: Case-control evaluation of the effectiveness of the G1P[8] human rotavirus vaccine during an outbreak of rotavirus G2P[4] infection in central Australia.
abstract: The human rotavirus vaccine was evaluated during an outbreak of rotavirus G2P[4] infection in central Australia. No overall protective effect against hospitalization was demonstrated, raising concerns over the durability of vaccine protection against heterotypic strains.
  
  
  BACKGROUND
  Two and a half years after commencing routine vaccination with human rotavirus vaccine, an outbreak of rotavirus G2P[4] infection occurred in central Australia. Vaccine effectiveness against a P[8]-containing strain (G9P[8]) had been demonstrated previously in this setting. This subsequent outbreak provided the opportunity to evaluate vaccine effectiveness against hospitalizations for a non-vaccine-related genotype in the same population.
  
  
  METHODS
  A case-control study was nested within a cohort of vaccine-eligible children listed on a population-based immunization register. Children with rotavirus-confirmed gastroenteritis were individually matched by date of birth and Indigenous status with 4 control subjects.
  
  
  RESULTS
  Forty-one cases met the inclusion criteria, and 21 were severe cases among infants aged <12 months. Nineteen (46%) of 41 case patients had received 2 doses of human rotavirus vaccine, compared with 87 (53%) of 164 control subjects. Vaccine effectiveness against rotavirus-related hospitalization was 19% (odds ratio, .81; 95% confidence interval, .32-2.05) for 2 doses compared with none. On secondary analysis, there was evidence of a protective effect against disease complicated by acidosis in the subset of infants aged <12 months (odds ratio, .15; 95% confidence interval, .03-.84).
  
  
  CONCLUSIONS
  Evidence was not found for an overall protective effect of human rotavirus vaccine against hospitalization for rotavirus disease in this setting. Post hoc analyses suggested a protective effect against severe disease in young infants.
authors.affiliation: Menzies School of Health Research and Charles Darwin University, Casuarina, Melbourne, Australia. thomas.snelling@menzies.edu.au
authors.forename: T L
authors.initials: TL
authors.lastname: Snelling
authors.forename: R M
authors.initials: RM
authors.lastname: Andrews
authors.forename: C D
authors.initials: CD
authors.lastname: Kirkwood
authors.forename: S
authors.initials: S
authors.lastname: Culvenor
authors.forename: J R
authors.initials: JR
authors.lastname: Carapetis
mesh_terms: D001315:Australia / Q000453:epidemiology; D016022:Case-Control Studies; D004196:Disease Outbreaks; D005260:Female; D005838:Genotype; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D008297:Male; D012401:Rotavirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000008:administration & dosage* / Q000276:immunology*
chemical_list: D022243:Rotavirus Vaccines