Comments: The trial explores the possibility of adding maternal pertussis immunization to the vaccination schedule as a first infant dose in order to reduce the possibility of infection before the first dose administered to the infant. However, it also suggests that the infant vaccination needs to be delayed beyond 3 months of age, in order to minimize interference with maternal antibodies. Introduction of a delayed infant pertussis immunization schedule would place neonates of unvaccinated women in a more vulnerable situation, and maternal coverage needs to be higher to protect all babies from pertussis from the first day of their life. Moreover, the study only addresses vaccination schedules using acellular pertussis vaccines in industrialized countries. The situation is completely different in LMICs where whole-cell pertussis (wP) vaccines are used in primary vaccination schedule and maternal immunization is still not well established. The blunting effect of maternal Tdap on wP containing primary vaccine series may be different from the findings in the current study.

Comments: The time between birth and initiation of the primary pertussis vaccination series at 6 to 8 weeks of age is the period of the greatest morbidity and mortality associated with pertussis disease. This study demonstrates that monovalent aP vaccine is immunogenic and safe in neonates, and may prove valuable for newborns whose mothers did not receive the Tdap vaccine during pregnancy. A birth dose of aP vaccine would significantly narrow the immunity gap between birth and 3 months of age, marking the critical period when infants are most vulnerable to severe pertussis infection. Thus, now we have two approaches to provide immunity cover to very young infants against pertussis – the maternal Tdap and aP at birth. Which one is superior? Can we utilize both the approaches in a synergistic way? However, both the options have undesirable impact on future infant immunization. The blunting effect of maternal Tdap on infant pertussis vaccination schedule even after booster dose, and the significantly reduced GMCs of the concomitantly administered antigens at 32 weeks with birth aP, are two main concerns. Furthermore, there is some evidence of a lower pertussis antibody level after completion of the primary vaccine series in infants born to mothers who had received Tdap within the 5 years prior to delivery.