A total of 150 eligible participants will be recruited in 3 sequential dose cohorts: low-dose 5 µg, medium-dose 10 µg, and high-dose 25 µg. In each dose cohorts, the participants will be randomized in a blinded manner into three arms (vaccine antigen with aluminum phosphate, vaccine antigen without Aluminum phosphate or placebo) in 2:2:1 ratio. All the participants will receive two intramuscular injections of 0.5 mL of the designated study vaccine or placebo on deltoid muscle, on Days 0 and 28.~The DSMB will review the safety data and approve dose escalation before investigational product injection of the next cohort is initiated.~The study primary objective is to evaluate the safety of the O Specific Polysaccharide recombinant Tetanus Toxoid Heavy Chain Fragment (OSP:rTTHc) cholera conjugate vaccine (CCV) after each dose vaccination.~The secondary objectives are:~To evaluate the Antibody response to OSP IgG against V. cholerae O1 after each dose vaccination of OSP:rTTHc CCV/placebo compared to pre-vaccination.~To evaluate the serum vibriocidal antibody titers against V. cholerae O1 Inaba and V. cholerae O1 Ogawa 4 weeks after each dose vaccination of OSP:rTTHc CCV/placebo compared to pre-vaccination.~The exploratory objectives are:~To describe the anti tetanus toxoid (anti-TT) Immunoglobulin G (IgG) 4 weeks after each dose vaccination of OSP:rTTHc CCV/placebo compared to pre-vaccination.~To describe memory B cell responses 4 and 28 weeks after first dose vaccination of OSP:rTTHc CCV/placebo compared to pre-vaccination.
This Phase I, first-in-human study is intended to primarily determine the safety of the dose range with or without Aluminum phosphate adjuvant expected to be needed for later clinical studies, to determine the nature of adverse reactions (i.e., safety profile) and to secondly assess the Aluminum phosphate humoral immune responses in non-endemic population to guide future dose selection.