Pertussis vaccination during pregnancy: Antibody persistence in infants

Area of Science:

• Immunology
• Maternal and Infant Health
• Vaccinology

Background:

• Maternal pertussis vaccination during pregnancy is recommended to protect infants.
• Infants born to vaccinated mothers have higher antibody levels at birth.
• The duration of this protection until infant vaccination is crucial.

Purpose of the Study:

• To assess the persistence of pertussis antibodies in infants born to mothers vaccinated with Tdap during pregnancy.
• To determine the antibody decline and half-life of maternal pertussis antibodies.
• To evaluate antibody levels before the infant's primary vaccination series.

Main Methods:

• Prospective cohort study at Hospital Clinic of Barcelona.
• Measurement of anti-pertussis toxin (PT) IgG by ELISA at delivery and at 2 months of age.
• Calculation of geometric mean concentration (GMC) and median half-life of antibodies.

Main Results:

• Infants showed a significant decline in anti-PT IgG GMC from peripartum levels (52.7) to 2 months of age (7.5).
• The median half-life of maternal antibodies was calculated to be 47 days.
• Over half (51.4%) of the infants still had detectable anti-PT IgG before their primary vaccination.

Conclusions:

• Maternal Tdap vaccination provides high antibody levels at birth, but these antibodies decline substantially by 2 months.
• The median antibody half-life suggests protection may be limited before infant primary vaccination.
• Further strategies may be needed to ensure sustained protection in early infancy.