title: Effectiveness of monovalent rotavirus vaccine (Rotarix) against severe diarrhea caused by serotypically unrelated G2P[4] strains in Brazil.
abstract: BACKGROUND. In a Latin American trial, a monovalent G1P[8] rotavirus vaccine showed high efficacy against severe rotavirus diarrhea. Protection was lower against serotypically unrelated G2P[4] strains, which circulated infrequently. This case-control study was undertaken to assess the effectiveness of this monovalent G1P[8] rotavirus vaccine against G2P[4] strains in Brazil. METHODS. Case patients were children with severe G2P[4] rotavirus diarrhea who presented at a hospital in Recife, Brazil, from March 2006 through September 2008. Vaccination rates among case patients were compared with rates among 2 groups of control participants-children with rotavirus-negative diarrhea and children admitted for acute respiratory tract infection (ARI)-to calculate vaccine effectiveness, after controlling for the birth month and year. RESULTS. We enrolled 70 G2P[4] rotavirus-positive case patients with severe diarrhea, 484 rotavirus-negative control participants with diarrhea, and 416 control participants with ARI, aged 6 months. Among children aged 6-11 months, the effectiveness of the vaccine against G2P[4] diarrhea was 77% (95% confidence interval [CI], 42%-91%) and 77% (95% CI, 43%-90%) among the rotavirus-negative control participants with diarrhea and control participants with ARI, respectively. Vaccine effectiveness in children aged 12 months decreased to -24% (95% CI, -190% to 47%) and 15% (95% CI, -101 to 64) among the rotavirus-negative control groups with diarrhea and ARI, respectively. CONCLUSIONS. This monovalent G1P[8] rotavirus vaccine was effective against severe G2P[4] rotavirus diarrhea among children aged 6-11 months. Effectiveness declined among children aged 12 months, which suggests waning immunity.
authors.affiliation: Instituto de Medicina Integral Prof Fernando Figueira, Recife, Brazil.
authors.forename: Jailson B
authors.initials: JB
authors.lastname: Correia
authors.forename: Manish M
authors.initials: MM
authors.lastname: Patel
authors.forename: Osamu
authors.initials: O
authors.lastname: Nakagomi
authors.forename: Fernanda M U
authors.initials: FM
authors.lastname: Montenegro
authors.forename: Eliane M
authors.initials: EM
authors.lastname: Germano
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Correia
authors.forename: Luis E
authors.initials: LE
authors.lastname: Cuevas
authors.forename: Umesh D
authors.initials: UD
authors.lastname: Parashar
authors.forename: Nigel A
authors.initials: NA
authors.lastname: Cunliffe
authors.forename: Toyoko
authors.initials: T
authors.lastname: Nakagomi
mesh_terms: D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D002675:Child, Preschool; D003967:Diarrhea / Q000517:prevention & control* / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016017:Odds Ratio; D012401:Rotavirus / Q000145:classification*; D012400:Rotavirus Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology*; D022243:Rotavirus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D012703:Serotyping
chemical_list: D022243:Rotavirus Vaccines