Clinical study of safety and immunogenicity of pentavalent DTP-HB-Hib vaccine administered by disposable-syringe jet injector in India

Introduction: We conducted a randomized, observer-blind, non-inferiority, parallel-group clinical study of diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b conjugate (pentavalent) vaccination of infants in India. Goals were to determine whether the seropositivity rate after vaccination via disposable-syringe jet injector (DSJI) was non-inferior to that via needle and syringe (N-S), and to compare the safety of vaccination by the two methods. Methods: Healthy children received a three-dose series of vaccine intramuscularly by DSJI or N-S beginning at 6-8 weeks of age. Immunoglobulin G antibody levels were measured by ELISA at 4-6 weeks after the third dose. The main secondary endpoint was safety, measured as injection site and systemic reactions. Discussion: The study was stopped early out of caution beyond that specified in the protocol stopping criteria, after the Data Safety Committee noted a higher frequency of injection site reactions, especially moderate and severe, in the DSJI group. As a result, 128 subjects-DSJI group 61; N-S group 67-completed the study, rather than the 340 planned, and the study was not sufficiently powered to compare immunogenicity endpoints for the groups. Descriptive statistics indicate that seropositivity induced by vaccination with the DSJI was similar to that of N-S for all five antigens. Pentavalent vaccine includes whole-cell pertussis vaccine and an aluminum adjuvant, which may have contributed to the higher number of local reactions with the DSJI. The reactions caused no serious or long-term sequelae, and may be more acceptable in other populations or circumstances.