I received the Tdap (combined tetanus, diphtheria, pertussis) vaccination in the past 10 years. Why do I need to get another one while I’m pregnant?
Pertussis, commonly called whooping cough, is a highly contagious bacterial infection caused by the bacteria Bordetella pertussis, which has been on the rise in recent years. It causes a severe cough, which produces a high-pitched “whoop” sound during coughing fits in infected individuals. Significant morbidity and mortality can be associated with the disease but is mostly confined to infants and small children, as most adults have been immunized against the infection. Previous recommendations by the medical community involved vaccination of women postpartum, as well as all of their close contacts, to prevent infection in newborns and young infants. This process was known as “cocooning” and was meant to protect infants, given that they do not start the pertussis vaccine series until 2 months old, leaving newborns particularly vulnerable to infection.
In response to the significant increase in pertussis infection and its associated morbidity in the US, the Advisory Committee on Immunization Practices (ACIP) published a new recommendation in February 2013 that all pregnant women receive the tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine during each pregnancy, regardless of previous vaccination history.
Administration of the vaccine during pregnancy, ideally between 27 to 36 weeks of gestation, maximizes passive antibody transfer from the mother to the newborn. With recent data demonstrating reduced immunogenicity in adults, revaccination during pregnancy becomes critical to boost the maternal antibody response. These maternal antibodies against the pertussis bacteria are then transferred to the growing fetus via the placenta as well as to her vunerable infant via breast milk.
There is no evidence of adverse fetal or neonatal outcomes from vaccination with the inactivated pertussis vaccine and a significant body of research supports its use in pregnant women. The American College of Obstetricians and Gynecologists (ACOG) enthusiastically supports the new vaccine recommendation and published an updated Committee Opinion in June 2013 detailing their position. In addition to vaccinating pregnant women, ACOG and the ACIP continue to recommend vaccination of close family members and direct caregivers in a further effort to prevent newborn infection.
Dr. Jamie L. Morgan is an OBGYN practicing in Dallas, TX