title: Dose response and efficacy of a live, attenuated human rotavirus vaccine in Mexican infants.
abstract: OBJECTIVE
  Immunization against rotavirus has been proposed as the most cost-effective intervention to reduce the disease burden associated with this infection worldwide. The objective of this study was to determine the dose response, immunogenicity, and efficacy of 2 doses of an oral, attenuated monovalent G1[P8] human rotavirus vaccine in children from the same setting in Mexico, where the natural protection against rotavirus infection was studied.
  
  
  METHODS
  From June 2001 through May 2003, 405 healthy infants were randomly assigned to 1 of 3 vaccine groups (virus concentrations 10(4.7), 10(5.2), and 10(5.8) infectious units) and to a placebo group and were monitored to the age of 2 years. The vaccine/placebo was administered concurrently with diphtheria-tetanus toxoid-pertussis/hepatitis B/Haemophilus influenzae type b vaccine at 2 and 4 months of age. After the administration of the first vaccine/placebo dose, weekly home visits to collect information regarding infant health were conducted. Stool samples were collected during each gastroenteritis episode and tested for rotavirus antigen and serotype.
  
  
  RESULTS
  The vaccine was well tolerated and induced a greater rate of seroconversion than observed in infants who received placebo. For the pooled vaccine groups, efficacy after 2 oral doses was 80% and 95% against any and severe rotavirus gastroenteritis, respectively. Efficacy was 100% against severe rotavirus gastroenteritis and 70% against severe gastroenteritis of any cause with the vaccine at the highest virus concentration (10(5.8) infectious units). The predominant infecting rotavirus serotype in this cohort was wild-type G1 (85%). Adverse events, including fever, irritability, loss of appetite, cough, diarrhea, and vomiting, were similar among vaccinees and placebo recipients.
  
  
  CONCLUSIONS
  This new oral, live, attenuated human rotavirus vaccine was safe, immunogenic, and highly efficacious in preventing any and, more importantly, severe rotavirus gastroenteritis in healthy infants. This vaccine produced comparable protection to natural infection.
authors.affiliation: Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubirán, Mexico City, Mexico. gmrps@servidor.unam.mx
authors.forename: Guillermo M
authors.initials: GM
authors.lastname: Ruiz-Palacios
authors.forename: M Lourdes
authors.initials: ML
authors.lastname: Guerrero
authors.forename: Aurora
authors.initials: A
authors.lastname: Bautista-Márquez
authors.forename: Hilda
authors.initials: H
authors.lastname: Ortega-Gallegos
authors.forename: Fernando
authors.initials: F
authors.lastname: Tuz-Dzib
authors.forename: Leticia
authors.initials: L
authors.lastname: Reyes-González
authors.forename: Gustavo
authors.initials: G
authors.lastname: Rosales-Pedraza
authors.forename: Julia
authors.initials: J
authors.lastname: Martínez-López
authors.forename: Erika
authors.initials: E
authors.lastname: Castañón-Acosta
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Cervantes
authors.forename: SueAnn
authors.initials: S
authors.lastname: Costa-Clemens
authors.forename: Beatrice
authors.initials: B
authors.lastname: DeVos
mesh_terms: D000284:Administration, Oral; D004306:Dose-Response Relationship, Immunologic; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D005759:Gastroenteritis / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D006801:Humans; D007223:Infant; D008297:Male; D008800:Mexico / Q000453:epidemiology; D011446:Prospective Studies; D012400:Rotavirus Infections / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000008:administration & dosage* / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D022243:Rotavirus Vaccines; D014613:Vaccines, Attenuated