Randomized, double-blind placebo-controlled trial to evaluate the safety and immunogenicity of combined Salmonella typhi Ty21a and Vibrio cholerae CVD 103-HgR live oral vaccines

Abstract

Healthy adults (n = 330) were randomized to receive either a bivalent vaccine composed of Vibrio cholerae CVD 103-HgR and Salmonella typhi Ty21a or a placebo. The combined vaccine was well tolerated. Approximately 80% of vaccinees manifested a significant rise in anti-S. typhi immunoglobulin G or immunoglobulin A lipopolysaccharide antibody levels. Significant (fourfold or greater) rises in anti-Inaba or anti-Ogawa vibriocidal antibody titer were achieved by 94 and 80% of vaccine recipients, respectively. Elevated baseline vibriocidal antibody liters showed a modest suppressive effect on the rate of seroconversion.