The safety of the vaccine was documented in an age descending study in Bangladesh encompassing 475 subjects.

The study showed that two doses of ETVAX ® with dmLT were immunogenic for all vaccine antigens in all age groups and the study showed a strong immune response, exceeding our expectations, was demonstrated. The results further showed a correlation between age and immune responses. The strongest response against all antigens was observed in adults and moderately decreased by age.The immune responses did correlate with age such that responses were most pronounced against all antigens in adults and responses decreased moderately with age. Immune responses in those 6 to 11 months of age were lowest among all study age groups but still consistently above placebo responses. A significant dmLT driven early onset of immunity was shown in the youngest age. Overall, a significant faecal secretory IgA immune responses were recorded against all vaccine antigens in infants. Addition of dmLT enhanced the magnitude, breadth, and kinetics of immune responses in infants. The youngest age group the study showed that dmLT driven significant early onset of immunity.

F. Qadri, Lancet Infect Dis 2019. Safety and immunogenicity of the oral, inactivated, enterotoxigenic Escherichia coli vaccine ETVAX in Bangladeshi children and infants: a double-blind, randomised, placebo-controlled phase 1/2 trial

M.Akhtar, Vaccine 2018. Evaluation of the safety and immunogenicity of the oral inactivated multivalent enterotoxigenic Escherichia coli vaccine ETVAX in Bangladeshi adults in a double-blind, randomized, placebo-controlled Phase I trial using electrochemiluminescence and ELISA assays for immunogenicity analyses.