title: Immunogenicity of a live-attenuated human rotavirus RIX4414 vaccine with or without buffering agent.
abstract: OBJECTIVE
  The lyophilized form of the human rotavirus RIX4414 vaccine (Rotarix()) is usually reconstituted with a liquid calcium carbonate (CaCO(3)) buffer and administered orally. However, errors in the reconstitution could occur (e.g. reconstituted with water instead of CaCO(3) buffer) or the buffer might be temporarily unavailable in few instances. This study was conducted to evaluate the immunogenicity of the RIX4414 vaccine if the vaccine was reconstituted with other agents (e.g., water) instead of CaCO(3) buffer.
  
  
  RESULTS
  There was no statistical difference detected between RIX4414 vaccine reconstituted with buffer or water in vaccine take or in seroconversion rate. The anti-rotavirus Immunoglobulin A (IgA) seroconversion rate 2 months post-Dose 2 was 84.7% (95% CI: 78.1-90.0) for the group with buffer and 78.6% (95% CI: 71.2-84.8) for the group with water. Solicited and unsolicited symptoms reported were similar across groups. No vaccine related serious adverse events (SAEs) were reported.
  
  
  METHODS
  Healthy infants aged 6-12 weeks, received two oral doses of the RIX4414 vaccine/placebo, reconstituted either with injectable water or CaCO(3) buffer according to a 0, 2 month schedule. Seroconversion rates in terms of anti-RV IgA antibody levels (cut off: >/=20 U/ml by ELISA) and vaccine take were calculated 2 months post-Dose 2. Solicited and unsolicited symptoms reported during the 15- and 31-day follow-up period after each dose and SAE s reported during the entire study period were recorded.
  
  
  CONCLUSIONS
  Administration of RIX4414 vaccine in the absence of CaCO(3) buffer was shown to be well tolerated and immunogenic in Thai infants.
authors.affiliation: Pediatric Infectious Disease Unit, Phramongkutklao Hospital, Bangkok, Thailand.
authors.forename: Angkool
authors.initials: A
authors.lastname: Kerdpanich
authors.forename: Kulkanya
authors.initials: K
authors.lastname: Chokephaibulkit
authors.forename: Veerachai
authors.initials: V
authors.lastname: Watanaveeradej
authors.forename: Nirun
authors.initials: N
authors.lastname: Vanprapar
authors.forename: Sriluck
authors.initials: S
authors.lastname: Simasathien
authors.forename: Nopaorn
authors.initials: N
authors.lastname: Phavichitr
authors.forename: Hans L
authors.initials: HL
authors.lastname: Bock
authors.forename: Silvia
authors.initials: S
authors.lastname: Damaso
authors.forename: Yanee
authors.initials: Y
authors.lastname: Hutagalung
authors.forename: Htay-Htay
authors.initials: HH
authors.lastname: Han