Pertussis, diphtheria, and tetanus antibodies seroprevalence in pregnant women and neonates, as a preliminary data for introduction of preconception or prenatal DTaP vaccination among Japanese society.

An increasing number of countries have been introducing acellular pertussis vaccination during pregnancy for the prevention of neonatal pertussis. In response to the fact that infantile pertussis cases of 0-5 months age groups remained unchanged despite the universal vaccination program, prenatal pertussis vaccination has been a rising issue in Japan. Hence, we investigated the seroprevalence of pertussis, diphtheria, and tetanus antibodies in Japanese pregnant women and neonates, and evaluated the necessity of diphtheria-tetanus-acellular pertussis (DTaP) vaccination during the preconception or prenatal period. Maternal PT-IgG (EIA) and FHA-IgG (EIA) for the first trimester, within 1 week after delivery, and cord blood were collected, along with colostrum pertussis-IgA (ELISA), diphtheria-IgG (EIA), tetanus-IgG (EIA), and blood samples from the first trimester. The maternal seroprevalence of PT-IgG and FHA-IgG was 69 % and 75 %, respectively. All tested participants were positive for diphtheria-IgG and tetanus-IgG (100 %). First trimester PT-IgG/FHA-IgG antibody titers were significantly associated with cord blood PT-IgG/FHA-IgG titers (P < 0.001). We found that pertussis seroprevalence among pregnant Japanese women was approximately 70 %. The antibody seropositivity rate of pertussis was lower than that of diphtheria and tetanus. Fetal acquired passive immunity against pertussis is higher when the level of maternal antibody in the first trimester is sufficient. At least 30 % of study population did not reach to the threshold value to provide sufficient pertussis immunity for the neonates and themselves. The acellular pertussis vaccine (DTaP) approved in Japan lacks safety information for pregnancy, hence, a solution for prompt administration of prenatal acellular pertussis vaccination might be introducing DTaP in the preconception period.