Effect of Probiotic on Immunogenicity of Oral Cholera Vaccine
Condition: Cholera
MeSH terms: Cholera
Study type: Interventional

Summary: 
      Cholera is a major health problem of many developing countries and marked increase in the
      prevalence has been seen on all continents in the last decade (WHO 1998). There is a great
      need for an appropriate vaccine to protect children the principal suffers in endemic
      countries, from the live threatening consequences of cholera. The B subunit-whole cell killed
      vaccine (Dukoral) developed in Sweden and used in field trials all over the world. It is
      licensed in many counties of the world and recommended by WHO. Protective efficacy to the
      killed vaccine has been demonstrated in adults in Bangladesh as well as in other countries,
      but less so in children (Clemens et al. 1986). Thus there is an urgency for developing
      strategies to improve the immunogenicity of vaccines especially for protection of children in
      cholera endemic countries of the world. Different options for improved cholera vaccines are
      being considered including new and improved formulations of killed or live oral candidate
      vaccines (Qadri et al. 2004, Sack et al. 1997, Levine et al. 1993) as well as the use of
      micronutrient supplementation during the course of immunization (Albert et al. 2003, Karlsen
      et al. 2003, Qadri et al. 2004). Another option that appears promising is the use of
      probiotics as adjunct to oral immunization based on the understanding that these agents could
      improve the mucosal immune responses, both innate and adaptive and help reducing inflammation
      (Blum and Schiffrin 2003, Fang et al. 2000). A therapeutic as well as preventive role of
      probiotics has been suggested from results of different studies using different probiotics
      that have been tested, usually lactic acid producing bacteria such as lactobacillus,
      Bifidobacterium and Steptococcus species. The supplemention of probiotics to infants may also
      have a prophylactic effect against acute diarrheal diseases. In pediatric populations, the
      effect of probiotic agents appears to be most significant against rotavirus diarrhea,
      suggesting that an immunological mechanism is responsible for the beneficial effects
      (Saavedra, 2000). In the present proposal we would like to examine if supplementation with
      the probiotic Bifidobacterium breve has a beneficial role in enhancing the immunogenicity of
      Dukoral in children. A two cell study will be conducted in which one group of children will
      be given B. breve every day for four weeks and another group will be given placebo. Two doses
      of the oral cholera vaccine will be administered at two week interval following initiation of
      the probiotic/placebo administration. Pre- and post- vaccination blood sample will be
      collected and assayed for immune response to the vaccine. The frequency and magnitude of the
      immune response to the vaccine will be compared among the two groups of children to assess
      whether the probiotic treatment enhances the immune responses to the vaccine. If probiotic
      supplemenation has a positive effect on the immune response it may be adopted as adjunct to
      enhance the efficacy of the cholera vaccine in immunization programmes and perhaps also of
      other enteric vaccines.
    


Intervention name(s): Whole cell killed cholera vaccine & probiotic
Intervention type(s): Biological
Intervention description(s): The oral cholera vaccine Dukoral will be administered to all study participants in two doses,two weeks between doses.Each dose of the formalin inactivated whole cell vaccine contains one mg of recombinant B subunit of cholera toxin(rCTB).The vaccine will be administered in bicarbonate-tartaric acid buffer to counteract the effect of low pH in the stomach.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Prevention
Keywords: Bifidobacterium breve; oral whole cell cholera vaccine; immunogenicity; Supplementation with probiotic improves vibriocidal antibody response in 2-5 year old childern given the killed oral cholera vaccine; Supplementation with probiotics results in improving the ASC responses to CT and LPS of V. cholerae O1