SAFETY AND IMMUNOGENICITY OF AN ORAL, KILLED ENTEROTOXIGENIC ESCHERICHIA-COLI - CHOLERA-TOXIN-B SUBUNIT VACCINE IN EGYPTIAN ADULTS

Enterotoxigenic Escherichia coli (ETEC) is the leading cause of bacter ial diarrhea in young children in developing countries. The safety and immunogenicity of a killed, oral ETEC vaccine consisting of whole cel ls plus recombinantly produced cholera toxin B subunit (rCTB) was eval uated in Egypt, which is endemic for ETEC diarrhea. Seventy-four healt hy Egyptian adults (21-45 years old) were randomized and received two doses of the ETEC/rCTB vaccine (E003) or placebo 2 weeks apart. The fr equency of adverse events after either dose did not differ by treatmen t group, and no severe adverse events were reported. After vaccination , peripheral blood IgA B cell responses to CTB (100%) and to vaccine c olonization factor antigens CFA/I (94%), CS4 (100%), CS2 (81%), and CS 1 (69%) were significantly higher than response rates for the placebo group. These favorable results in Egyptian adults indicate that the ET EC/rCTB vaccine is a promising candidate for evaluation in younger age groups in this setting.