Transplacental transfer of maternal antibodies following immunization with recombinant pertussis vaccines during pregnancy: Real-world evidence

Abstract

Aim/objective: This study investigates placental antibody transfer following recombinant pertussis vaccination in pregnancy in a real-world setting.

Methods: This postmarketing observational study recruited pregnant women vaccinated with monovalent recombinant acellular pertussis (aP) vaccine (aP_gen; n = 199) or combined to tetanus-diphtheria (TdaP_gen; n = 200), or Td-vaccine only (n = 54). Pregnancy, delivery, and neonatal outcomes were assessed. Cord blood was collected postdelivery and pertussis toxin (PT)-IgG, filamentous hemagglutinin (FHA)-IgG, and PT-neutralizing antibodies (PT-Nab) were assessed.

Results: No adverse pregnancy, delivery, or neonatal outcomes attributed to aP_gen, TdaP_gen, or Td vaccination were reported. High anti-PT antibody levels were detected in cord samples from women vaccinated with aP_gen (geometric mean concentration [GMC] PT-IgG 206.1 IU/ml, 95% confidence intervals [CI]: 164.3-258.6; geometric mean titer [GMT] PT-Nab 105.3 IU/ml, 95% CI: 81.7-135.8) or TdaP_gen (GMC PT-IgG 153.1 IU/ml, 95% CI: 129.1-181.5; GMT PT-Nab 81.5 IU/ml, 95% CI: 66.4-100.0). In the Td-only group, anti-PT antibodies were low (GMC PT-IgG 6.5 IU/ml, 95% CI: 4.9-8.8; GMT PT-Nab 3.8 IU/ml, 95% CI: 2.8-5.1). The same was found for FHA-IgG. Recombinant pertussis vaccination at <27 or 27-36 weeks gestation induced similar cord pertussis antibody levels.

Conclusion: This first real-world study confirms that recombinant pertussis vaccination in the second or third trimester of pregnancy results in high levels of passive immunity in infants. Thai Clinical Trial Registry: TCTR20200528006.

Keywords: Cord blood; Maternal immunization; Pertussis; Placental transfer; Pregnancy; Recombinant vaccine.