Kinetics of maternal pertussis-specific antibodies in infants of mothers vaccinated with tetanus, diphtheria and acellular pertussis (Tdap) during pregnancy. Issue 37 (18th August 2020)

• Record Type: Journal Article
• Authors: Healy, C. Mary; Rench, Marcia A.; Swaim, Laurie S.; Timmins, Audra; Vyas, Anuja; Sangi-Haghpeykar, Haleh; Ng, Nancy; Rajam, Gowrisankar; Havers, Fiona; Schiffer, Jarad; Baker, Carol J.
• Is Part Of: Vaccine. Volume 38:Issue 37(2020)
• Page Start: 5955
• Page End: 5961
• Publication Date: 2020-08-18
• Subjects: Tdap -- Pertussis -- Maternal vaccination -- Passive protection -- Infants; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2020.06.050
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: Half-life of pertussis antibodies in neonates after maternal Tdap vaccination is ∼29–36 days. There is substantial individual variability in pertussis antibody levels. 6-week infant antibody levels exceed maternal pre-Tdap levels, despite this short half-life. These antibody levels may be sufficient to protect infants from pertussis through age 2 months. Abstract: Background: Kinetics of Tdap-induced maternally-derived antibodies in infants are poorly understood. Pre-Tdap era data suggest that maternal pertussis antibodies in infants have a half-life of approximately 5–6 weeks. Methods: 34 mother-infant pairs had blood collected before maternal Tdap vaccination, 4 weeks later, at delivery (maternal and cord), and at infant ages 3 and 6 weeks from June 2014-March 2015. Immunoglobulin G (IgG) to pertussis toxin (PT), filamentous hemagglutinin (FHA), fimbrial proteins (FIM) and pertactin (PRN) was quantified by multiplex luminex assay (IU/ml). Geometric mean concentrations (GMCs) with 95% confidence intervals (C.I.) and half-life of pertussis antibodies were calculated. Results: Tdap was administered to 34 women (mean age 31.1 years) at mean gestation 30.7 weeks (28–32.7). Mean neonatal gestation was 39.1 weeks (36–41.1) and mean birthweight was 3379 g (2580–4584). Four weeks post-Tdap vaccination, maternal pertussis-specific IgG GMCs increased ≥4-fold in 59%, 41%, 29% and 44% of women for PT, FHA, FIM and PRN, respectively, and then waned. The transplacental transport ratio of pertussis antibodies was 1.35 for PT, 1.41 for FHA, 1.31 for FIM and 1.36 for PRN. Between birth and age 6 weeks, infant serum GMC for PT-specific IgG decreased from 55.1 IU/mL (38.6–78.6) to 21.1 IU/ml (14.7–30.2), and the proportion of infants with PT levels ≥10 IU/ml fell from 97% to 67%. Half-life of pertussis-specific IgG in infants in days was 29.4 (95% CI 27.3–31.7) for PT, 29.8 (95% CI 27.7–32.2) for FHA, 31.2 (95% CI 28.9–33.7) for PRN, and 35.8 (95% CI 30.1–44.3) for FIM. Conclusion: The half-life of pertussis-specific antibodies in infants induced by maternal Tdap vaccination (29–36 days) is shorter than previously reported. Understanding how the durability of passively-acquired antibodies impacts infant susceptibility to pertussis and response to primary vaccination is critical to refine prevention strategies.