Oral, Inactivated, Whole Cell Enterotoxigenic Escherichia coli plus Cholera Toxin B Subunit Vaccine: Results of the Initial Evaluation in Children

Two randomized, double-blinded trials assessed the safety and immunogenicity of an oral, killed enterotoxigenic Escherichia coli (ETEC) plus cholera toxin B subunit vaccine in Egyptian children. Two doses of vaccine or E. coli K-12 were given 2 weeks apart to 105 6- to 12-yearolds and 97 2- to 5-year-olds. Safety was monitored for 3 days after each dose. Blood was collected before immunization and 7 days after each dose to measure immune responses. Few children reported postdosing symptoms, with no differences in the frequency of symptoms between treatment groups. Most vaccinees had an IgA antibody‐secreting cell response against colonization factor antigen I (100%, 6‐12 years; 95%, 2‐5 years), coli surface antigen 2 (92%, 6‐12 years; 83%, 2‐5 years), and coli surface antigen 4 (93%, 6‐12 years). Vaccination evoked a >4-fold rise in antitoxic IgA and IgG titers in 93% and 81% of children, respectively. In conclusion, the oral ETEC vaccine was safe and immunogenic in 2- to 12-year-old children, justifying further evaluation in infants.