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

Abstract

Background: Pertussis is a vaccine-preventable disease that affects infants and adults around the world despite high vaccination coverage. Objectives: The present study was preformed to assess pertussis seroprevalence in maternal serum and cord blood after delivery. Methods: 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. Results: 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 < 0.001, r = 0.66). This correlation, with regards to PT IgG, was also significant (P value < 0.001, r = 0.53). The geometric mean titer for FHA IgG in cord blood was 1.72 times higher than in mother's blood (P value of < 0.001). On the other hand, geometric mean titer for PT IgG in maternal blood was 3 folds higher than in cord blood (P value < 0.001). No correlations were found between the level of antibody and maternal age, parity, gestational age or neonate's birth weight (P > 0.05). Conclusions: 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.

Bordetella pertussis in School-Age Children, Adolescents, and Adults: A Systematic Review of Epidemiology, Burden, and Mortality in the Middle East

“…There were 8 surveillance studies and 16 serosurveillance studies of pertussis in the Middle East, including Iran [20][21][22][23][24][25][26][27][28][29][30][31][32][33], Israel [34][35][36], Iraq [37], United Arab Emirates (UAE) [38], and Turkey [39][40][41]. An overview of epidemiological/sero-epidemiological studies is shown in Table 1 for Iran and in Table 2 for the other countries with available data.…”

“…Among 288 pregnant women admitted to hospital in Iran in 2011-2012, 35% were positive for pertussis infection (PT IgG [ 24 IU/ml) [33]. In another study in Iran in 2016-2017, of 88 mothers with a mean age of 29 years, 4.5% had evidence of pertussis infection (PT IgG level unspecified); overall, 81% were vaccinated in childhood suggesting that vaccine-acquired immunity had waned over time [27].…”