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Clin Infect Dis. 2016 Apr 1;62(7):829-836. doi: 10.1093/cid/ciw027. Epub 2016 Jan 20.

Maternal Immunization Earlier in Pregnancy Maximizes Antibody Transfer and Expected Infant Seropositivity Against Pertussis.

Author information

1
Center for Vaccinology and Neonatal Immunology, Department of Pediatrics and Pathology-Immunology.
2
Departments of Neonatology and Pediatric Intensive Care.
3
Pediatrics, Children's Hospital of Geneva.
4
Centerfor Vaccinology and Neonatal Immunology, Department of Pediatrics and Pathology-Immunology.
5
Department of Gynecology and Obstetrics.
6
Clinical Research Center, University Hospitals of Geneva and Faculty of Medicine, University of Geneva, Switzerland.
7
BioNet-Asia Co, Ltd, Bangkok, Thailand.

Abstract

BACKGROUND:

Maternal immunization against pertussis is currently recommended after the 26th gestational week (GW). Data on the optimal timing of maternal immunization are inconsistent.

METHODS:

We conducted a prospective observational noninferiority study comparing the influence of second-trimester (GW 13-25) vs third-trimester (≥GW 26) tetanus-diphtheria-acellular pertussis (Tdap) immunization in pregnant women who delivered at term. Geometric mean concentrations (GMCs) of cord blood antibodies to recombinant pertussis toxin (PT) and filamentous hemagglutinin (FHA) were assessed by enzyme-linked immunosorbent assay. The primary endpoint were GMCs and expected infant seropositivity rates, defined by birth anti-PT >30 enzyme-linked immunosorbent assay units (EU)/mL to confer seropositivity until 3 months of age.

RESULTS:

We included 335 women (mean age, 31.0 ± 5.1 years; mean gestational age, 39.3 ± 1.3 GW) previously immunized with Tdap in the second (n = 122) or third (n = 213) trimester. Anti-PT and anti-FHA GMCs were higher following second- vs third-trimester immunization (PT: 57.1 EU/mL [95% confidence interval {CI}, 47.8-68.2] vs 31.1 EU/mL [95% CI, 25.7-37.7], P < .001; FHA: 284.4 EU/mL [95% CI, 241.3-335.2] vs 140.2 EU/mL [95% CI, 115.3-170.3], P < .001). The adjusted GMC ratios after second- vs third-trimester immunization differed significantly (PT: 1.9 [95% CI, 1.4-2.5]; FHA: 2.2 [95% CI, 1.7-3.0], P < .001). Expected infant seropositivity rates reached 80% vs 55% following second- vs third-trimester immunization (adjusted odds ratio, 3.7 [95% CI, 2.1-6.5], P < .001).

CONCLUSIONS:

Early second-trimester maternal Tdap immunization significantly increased neonatal antibodies. Recommending immunization from the second trimester onward would widen the immunization opportunity window and could improve seroprotection.

KEYWORDS:

maternal antibodies; maternal immunization; neonates; pertussis; pregnancy

PMID:
26797213
PMCID:
PMC4787611
DOI:
10.1093/cid/ciw027
[Indexed for MEDLINE]
Free PMC Article

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