Texas Star-SR: Attenuated Vibrio Cholerae Oral Vaccine Candidate

Abstract

The search continues for a cholera vaccine that is both safe and highly protective for a long duration. Experimental cholera challenge studies in volunteers with Vibrio cholerae Ogawa and Inaba strains of the classical biotype have demonstrated that an initial clinical cholera infection provides solid clinical and bacteriologic protection against re-challenge with either the homologous or heterologous serotype.^1–4 Significant protection was found to persist for at least three years, the longest interval tested.⁴ The rare isolation of vibrios from stool or jejunal fluid cultures of re-challenged volunteers and the infrequency of significant rises in serum or intestinal fluid antitoxin infer that antibacterial immune mechanisms limited proliferation of vibrios before they could produce enterotoxin.^2–4 These observations suggest that one promising approch toward immunologic control of cholera could be by way of development of attenuated, non-enterotoxinogenic V. cholerae strains employed as oral vaccines.