Updated Recommendations for Use of Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine (Tdap) in Pregnant Women and Persons Who Have or Anticipate Having Close Contact With an Infant Aged <12 Months

Advisory Committee on Immunization Practices (ACIP), 2011

Morbidity and Mortality Weekly Report. 2011;60(41):1424-1426. 

In This Article

Transplacental Maternal Antibodies

For infants, transplacentally transferred maternal antibodies might provide protection against pertussis in early life and before beginning the primary DTaP series. Several studies provide evidence supporting the existence of efficient transplacental transfer of pertussis antibodies.[7,11,12] Cord blood from newborn infants whose mothers received Tdap during pregnancy or before pregnancy had higher concentrations of pertussis antibodies when compared with cord blood from newborn infants of unvaccinated mothers.[7,11] The half-life of transferred maternal pertussis antibodies is approximately 6 weeks.[12] The effectiveness of maternal antipertussis antibodies in preventing infant pertussis is not yet known, but pertussis-specific antibodies likely confer protection and modify the severity of pertussis illness.[13,14] In addition, a woman vaccinated with Tdap during pregnancy likely will be protected at time of delivery, and therefore less likely to transmit pertussis to her infant. After receipt of Tdap, boosted pertussis-specific antibody levels peak after several weeks, followed by a decline over several months.[15,16] To optimize the concentration of maternal antibodies transferred to the fetus, ACIP concluded that unvaccinated pregnant women should receive Tdap, preferably in the third or late second (after 20 weeks gestation) trimester.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.