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TOPLINE:

Vaccinating women with tetanus-diphtheria-acellular pertussis–inactivated polio virus (Tdap-IPV) during pregnancy in a sub–Saharan African setting was safe, well tolerated and boosted pertussis-specific antibody responses among infants in early life.

METHODOLOGY:

• Researchers conducted a phase 4 trial to assess the effect of pertussis vaccination during pregnancy on the immunogenicity of primary acellular or whole-cell pertussis vaccines in a West African cohort.
• A total of 343 women were enrolled between February 2019 and May 2021 and randomly assigned to receive either tetanus toxoid (n = 172) or Tdap-IPV (n = 171) during 28-34 weeks of gestation.
• Infants born to women in each group were subsequently randomly assigned to receive either the diphtheria-tetanus-acellular pertussis (DTaP) vaccine or the diphtheria-tetanus–whole-cell pertussis (DTwP) vaccine at 8, 12, and 16 weeks of age.
• The primary outcome was the geometric mean concentration (GMC) of infant pertussis toxin–specific antibodies at 20 weeks and 9 months of age, assessed among infants who received all three primary doses of either DTaP or DTwP.
• Adverse events in mothers and infants were recorded once daily for 3 days after each vaccine dose. Pregnant women were assessed in an additional visit of 7 days after vaccination.

TAKEAWAY:

• At 20 weeks, among infants born to Tdap-IPV–immunized mothers, those who received DTwP vaccines had nearly threefold lower anti–pertussis toxin immunoglobulin G (IgG) levels than those who received DTaP vaccines (adjusted geometric mean ratio [GMR], 0.28; 98.75% CI, 0.16-0.50); that persisted through 9 months (adjusted GMR, 0.31; 98.75% CI, 0.17-0.55).
• Among infants born to tetanus toxoid–immunized mothers, postvaccination GMCs of anti–pertussis toxin IgG at 9 months were twice as higher in those who received DTwP vaccines than in those who received DTaP vaccines (adjusted GMR, 2.02; 98.75% CI, 1.15-3.55).
• There was a significant blunting of pertussis toxin neutralizing activity, serum bactericidal activity, total pertussis-specific antibody binding, and memory B-cell responses among DTwP-vaccinated infants born to Tdap-IPV–vaccinated mothers.
• The vaccines were well tolerated by both mothers and their infants, with minimal reactogenicity. No grade 3-4 adverse events were reported, and no serious adverse events were attributed to the vaccine.

IN PRACTICE:

“The immunogenicity data generated support the existing data regarding the clinical effectiveness of pertussis immunization programs in pregnancy,” the authors wrote.

SOURCE:

This study was led by Anja Saso, MBBS, Vaccines and Immunity Theme, MRC Unit The Gambia, London School of Hygiene & Tropical Medicine, Fajara, the Gambia. It was published online on March 25, 2025, in The Lancet Infectious Diseases.

LIMITATIONS:

This study did not achieve the planned sample size of 600 mother-infant pairs due to the SARS-CoV-2–related lockdown and public health measures in the Gambia in 2020. Additionally, some postvaccination home visits were conducted by telephone, potentially affecting the accuracy of reactogenicity assessments. Follow-up was limited to 9 months of age, and longer-term immunological responses were not assessed.

DISCLOSURES:

This study was conducted as part of the Pertussis Correlates of Protection Europe consortium, which was funded by the Innovative Medicines Initiative 2 Joint Undertaking under a grant agreement. Two authors reported receiving funding from various sources.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.