Mohammed-Jafar Saffar, Abolghasem Ajami, Narges Moslemizadah, Hiva Saffar and Ali-Reza Khalilian
Background: Despite high vaccine coverage the incidence of pertussis is increasing, especially in infants too young to be actively immunized. We sought to determine whether prepregnancy pertussis boosting could provide higher levels of maternal antibodies to offspring compared with that before one, and also, possible influences on infant immune response to whole-cell pertussis immunization. Methods: A total of 114 childbearing age women, candidate for pregnancy were boosted with one dose of diphtheria - tetanus, pertussis adult formulation vaccine (dTap). Blood samples were obtained at before and after vaccination and at months of 1, 12, 28, and 43. Paired maternal-neonatal sera were also collected at the time of delivery. Moreover, blood was drawn to examine the infant immune response to scheduled whole - cell pertussis (wP) vaccine after receiving the first, third and fourth dose of the vaccine. Antibodies to pertussis antigens were measured by ELISA method and paired t-test was applied to analyze the data. Results: Seroprevalence rate and the mean concentration of antibodies (MCA) before boosting were 69.3% and 68.19 EU/ml which increased to 93.8% and 152.82 EU/mL after vaccination, respectively. After 43 month, 72.3% of vaccinees preserved significantly higher (76.71 vs. 68.19 Eu/ml) antibody levels compared with prebooster MCA level. Efficient placental transfer of antibody to the offsprings was observed, however, infants immune response to wP vaccine was not influenced by maternal antibodies. Conclusion: Targeted prepregnancy pertussis immunization provides a higher antibody level at delivery and importantly does not affect infants immune response to wP immunization.