Evaluation of a probiotics, Bifidobacterium breve BBG-01, for enhancement of immunogenicity of an oral inactivated cholera vaccine and safety: a randomized, double-blind, placebo-controlled trial in Bangladeshi children under 5 years of age.

To evaluate the probiotic, Bifidobacterium breve strain Yakult (BBG-01), for safety and enhancement of immunogenicity in an oral inactivated cholera vaccine, a randomized double-blind placebo-controlled study was performed. Bangladeshi children under 5-year-old received BBG-01 or placebo for 4 weeks with two doses of oral cholera vaccine. Serum/fecal antibodies and fecal bacterial flora in the study participants were monitored. All adverse events were mild and transient and had no significant difference between the two groups. Immunological responses were similar comparing the two groups. A negative correlation between Bifidobacterium and Enterobacteriaceae in the probiotic group suggests a possible involvement of BBG-01 in alteration of the enteric bacterial flora. In conclusion, BBG-01 is well tolerated by Bangladeshi children although the post vaccinal immunostimulatory effect of BBG-01 was not evident.