Seroprevalence of Pertussis Antibodies in Maternal and Cord Blood Sample of Their Newborns

Pertussis is a vaccine-preventable disease that affects infants and adults around the world despite high vaccination coverage.
The present study was preformed to assess pertussis seroprevalence in maternal serum and cord blood after delivery.
A cross-sectional, descriptive analytical study was carried out in a single urban hospital (Tehran-Iran), during years 2015 and 2016. The target population included term-healthy neonates with their mothers. Immediately after birth, mother’s blood was tested for PT IgG, FHA IgG, FHA IgA, and PT IgA, and umbilical cord blood was tested for PT IgG and FHA IgG by the enzyme linked immunosorbent assay (ELISA). Potentially protective antibody levels were evaluated.
Eighty-eight parturient mother-neonate pairs entered the study. Seventy-two mothers (81.8%) had childhood vaccination yet with regards to negative PT IgA and FHA IgA (90.9% and 95.5%), more than 90% of them did not show antibodies related to acute pertussis infection. According to the cutoff, PT IgG in 33%, 13.6%, and 53.4% was negative, equivocal, and positive, respectively. Based on the cord blood PT-IgG concentration, 61.4% of newborns were also unprotected against B. pertussis. A significant positive correlation was observed between mother and neonate’s FHA IgG (P value 0.05).
This study demonstrated a low level of immunity against B. pertussis in pregnant females, which may increase the risk of pertussis in very young infants. Implementing strategies, such as Tdap vaccination during the antenatal period, seems to be of great importance.