Comparison of Bordetella pertussis Antibody Levels in Pregnant Women and Umbilical Cord Blood: A Multicenter Study

Background: In countries where pertussis vaccination is not administered during pregnancy, the determination of pertussis antibody levels in pregnant women is very important in terms of knowing the current seroepidemiology and potential strategies for immunizations. Methods: We included 396 pregnant women who were admitted to 4 different obstetrics and gynecology clinics. Anti-Bordetella pertussis toxin (PT) IgG and anti-Bordetella pertussis filamentous hemagglutinin IgG levels in maternal and cord blood pairs were determined by the ELISA method. Results: Venous blood serum anti-PT level was below 5 IU/mL in 58.8%, 5–40 IU/mL in 34.8%, 40–100 IU/mL in 5.1% and >100 IU/mL in 1.3% of pregnant women. Cord blood serum anti-PT level was below 5 IU/mL in 47.7%, 5–40 IU/mL in 44.5%, 40–100 IU/mL in 6.8% and >100 IU/mL in 1% of pregnant women. In our study, the anti-PT level was found below 40 IU/mL in 93.6% of pregnant women and 92.2% of cord blood. Our study found the anti-filamentous hemagglutinin level below 40 IU/mL in 81% of pregnant women and 66.2% of cord blood. Conclusions: Although it is known that pertussis causes serious morbidity and mortality in young infants all over the world and that the most effective and reliable way to prevent it is vaccination of pregnant women, it is a remarkable contradiction that pertussis vaccination rates and therefore seropositivity rates in pregnant women are very low.