SMFM Clinical Practice Guidelines Tdap Vaccination in pregnancy Society of Maternal Fetal Medicine with the assistance of Neil Silverman, MD Published in Contemporary OB/GYN / April 2014

How and why have pertussis vaccine recommendations for pregnancy changed?  The most recent ACIP/CDC recommendations were issued in February 2013, and were developed after careful consideration of newer data related to efficacy and durability of the current pertussis (Tdap) vaccine.  In reviewing nationally reported data for pertussis cases in 2012, the CDC was concerned that infection and death rates had surpassed the most recent peak year of 2010: For 2012, 41,880 pertussis cases and 14 deaths in infants aged <12 months were reported.  Vaccination rates with Tdap among pregnant women have been low. One survey of pregnant women from August 2011 to April 2012 estimated that only 2.6% of women had received Tdap during their most recent pregnancy.  Antipertussis antibodies available for passive transfer have been shown to be even shorter-lived than previously thought, with substantial decay of levels after 1 year.  Newer data strongly suggest that Tdap vaccination in one pregnancy would not provide high-enough antibody levels to persist and protect newborns delivered in subsequent pregnancies,19 although maternal cellular immunity would be expected to be more durable.

Is it safe to give repeated doses of Tdap?  Published data on administration of 2 doses of Tdap and on multiple doses of a tetanus-toxoid-containing vaccine show that receipt of a second dose of Tdap at a 5- or 10-year interval in healthy nonpregnant adolescents and adults was well tolerated.  Injection-site pain was the most commonly reported adverse event.  Although 94% of subjects reported at least one injection-site event such as erythema, swelling, and pain, these rates were not significantly higher after a second dose compared to the first vaccine dose, and only 4%–5% of recipients reported grade 3/3 pain.  A theoretical risk exists for more severe local reactions in pregnant women who receive Tdap vaccine during multiple closely spaced pregnancies.  These can include the Arthus reaction, a type III hypersensitivity reaction that manifests as local vasculitis due to deposition of IgG- based immune complexes in dermal blood vessels. The risk of this adverse effect may be increased with higher levels of preexisting antibody.  Because most of the data evaluating this risk are historical and relate to vaccines with much higher levels of tetanus toxoid than in current preparations, the already-low risk of these types of adverse effects is felt to be significantly lower today than previously reported.

Are there special situations to be considered for using Tdap during pregnancy?  Pregnant women due for a tetanus booster. If Td booster vaccination would be considered during pregnancy, Tdap should be used, optimally at 27– 36 weeks’ gestation.  Wound management during pregnancy. If a tetanus-toxoid-containing vaccine is being given for wound management during pregnancy (if ≥5 years since previous Td booster), Tdap should be given.

Summary  Tdap vaccination is both safe and recommended for all pregnant women during every pregnancy, regardless of the timing of their last Tdap immunization.  Pregnant women should ideally receive the Tdap vaccine at 27–36 weeks’ gestation.

 The practice of medicine continues to evolve, and individual circumstances will vary. This opinion reflects information available at the time of its submission for publication and is neither designed nor intended to establish an exclusive standard of perinatal care. This presentation is not expected to reflect the opinions of all members of the Society for Maternal-Fetal Medicine.  These slides are for personal, non- commercial and educational use only Disclaimer

Disclosures  This opinion was developed by the Publications Committee of the Society for Maternal Fetal Medicine with the assistance of Stanley M. Berry, MD, Joanne Stone, MD, Mary Norton, MD, Donna Johnson, MD, and Vincenzo Berghella, MD, and was approved by the executive committee of the society on March 11, Dr Berghella and each member of the publications committee (Vincenzo Berghella, MD [chair], Sean Blackwell, MD [vice-chair], Brenna Anderson, MD, Suneet P. Chauhan, MD, Jodi Dashe, MD, Cynthia Gyamfi-Bannerman, MD, Donna Johnson, MD, Sarah Little, MD, Kate Menard, MD, Mary Norton, MD, George Saade, MD, Neil Silverman, MD, Hyagriv Simhan, MD, Joanne Stone, MD, Alan Tita, MD, Michael Varner, MD) have submitted a conflict of interest disclosure delineating personal, professional, and/or business interests that might be perceived as a real or potential conflict of interest in relation to this publication.