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 immunogenicit y of an oral, killed enterotoxigenic Escherichia coli (ETEC) plus cholera t oxin B subunit vaccine in Egyptian children. Two doses of vaccine or E. col i K-12 were given 2 weeks apart to 105 6- to 12-year-olds and 97 2- to 5-ye ar-olds. Safety was monitored for 3 days after each dose. Blood was collect ed before immunization and 7 days after each dose to measure immune respons es. Few children reported postdosing symptoms, with no differences in the f requency of symptoms between treatment groups. Most vaccinees had an IgA an tibody-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 evoke d a greater than or equal to 4-fold rise in antitoxic IgA and IgG titers in 93% and 81% of children, respectively, In conclusion, the oral ETEC vaccin e was safe and immunogenic in 2- to 12-year-old children, justifying furthe r evaluation in infants.