title: Safety, immunogenicity, and protective efficacy of two doses of RIX4414 live attenuated human rotavirus vaccine in healthy infants.
abstract: OBJECTIVE
  To determine the safety, immunogenicity and efficacy of two doses of rotavirus vaccine in healthy Brazilian infants.
  
  
  METHODS
  A randomized, multicenter, double-blind, placebo-controlled trial was conducted in Brazil, Mexico and Venezuela. Infants received two oral doses of vaccine or placebo at 2 and 4 months of age, concurrently with routine immunizations, except for oral poliomyelitis vaccine (OPV). This paper reports results from Belém, Brazil, where the number of subjects per group and the viral vaccine titers were: 194 (10(4.7) focus forming units - FFU), 196 (10(5.2) FFU), 194 (10(5.8) FFU) and 194 (placebo). Anti-rotavirus (anti-RV) antibody response was assessed in 307 subjects. Clinical severity of gastroenteritis episodes was measured using a 20-point scoring system with a score of >or= 11 defined as severe GE.
  
  
  RESULTS
  The rates of solicited general symptoms were similar in vaccine and placebo recipients. At 2 months after the second dose, a serum IgA response to RV occurred in 54.7 to 74.4% of vaccinees. No interference was seen in the immunogenicity of routine vaccines. Vaccine efficacy against any rotavirus gastroenteritis (RVGE) was 63.5% (95%CI 20.8-84.4) for the highest concentration (10(5.8) FFU). Efficacy was 81.5% (95%CI 44.5-95.4) against severe RVGE. At its highest concentration (10(5.8) FFU), RIX4414 provided 79.8% (95%CI 26.4-96.3) protection against severe RVGE by G9 strain.
  
  
  CONCLUSIONS
  RIX4414 was highly immunogenic with a low reactogenicity profile and did not interfere with seroresponse to diphtheria, tetanus, pertussis, hepatitis B and Hib antigens. Two doses of RIX4414 provided significant protection against severe GE caused by RV.
authors: Instituto Evandro Chagas, Secretaria de Vigilância em Saúde, Ministério da Saúde, Belém, PA, Brasil.
authors: Eliete C
authors: EC
authors: Araujo
authors: Sue Ann C
authors: SA
authors: Clemens
authors: Consuelo S
authors: CS
authors: Oliveira
authors: Maria Cleonice A
authors: MC
authors: Justino
authors: Pilar
authors: P
authors: Rubio
authors: Yvone B
authors: YB
authors: Gabbay
authors: Veronilce B
authors: VB
authors: da Silva
authors: Joana D P
authors: JD
authors: Mascarenhas
authors: Vânia L
authors: VL
authors: Noronha
authors: Ralf
authors: R
authors: Clemens
authors: Rosa Helena P
authors: RH
authors: Gusmão
authors: Nervo
authors: N
authors: Sanchez
authors: Talita Antônia F
authors: TA
authors: Monteiro
authors: Alexandre C
authors: AC
authors: Linhares
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D001938:Brazil; D004311:Double-Blind Method; D005759:Gastroenteritis / Q000517:prevention & control* / Q000821:virology; D006801:Humans; D007223:Infant; D008800:Mexico; D012401:Rotavirus / Q000276:immunology; D012400:Rotavirus Infections / Q000517:prevention & control*; D022243:Rotavirus Vaccines; D012720:Severity of Illness Index; D014613:Vaccines, Attenuated / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D014687:Venezuela
chemical_list: D000914:Antibodies, Viral; C492457:RIX4414 vaccine; D022243:Rotavirus Vaccines; D014613:Vaccines, Attenuated