Jones CE, Calvert A, Southern J, et al. - Researchers conducted this multi-center phase IV randomized clinical trial comparing anti-pertussis IgG responses following primary immunization in infants of mothers vaccinated with TdaP₅-IPV (low dose diphtheria toxoid, tetanus toxoid, acellular pertussis [five antigens] and inactivated polio) or TdaP₃-IPV in pregnancy (three pertussis antigens). They randomized 77 women to receive TdaP₅-IPV (n = 77) and 77 women to receive TdaP₃-IPV (n = 77) at 28–32 gestational weeks. Infants born to women vaccinated with TdaP₅-IPV and TdaP₃-IPV showed blunting of anti-pertussis toxin IgG response following primary immunization, with no difference between maternal vaccines. Resolution of the blunting effect occurred by 13 months of age. Accounting these results, countries may determine the pertussis-containing vaccine to be recommended for use in pregnancy.