Pertussis vaccine in pregnant women: safety and uptake

Abstract

Pertussis continues to be an important cause of morbidity and mortality in children worldwide, particularly among infants too young to be vaccinated or who are unvaccinated and unprotected by naturally acquired passive antibodies from their mothers. Vaccination of women during pregnancy with an adult formulation of acellular pertussis vaccine in combination with tetanus and diphtheria toxoids (Tdap [tetanus, reduced diphtheria and acellular pertussis vaccine]) is recommended in several industrialized countries to boost the levels of maternal antibodies that are transferred transplacentally and protect infants during the period of life when they are more likely to succumb to pertussis. Data from clinical and epidemiologic studies are supportive of the safety and effectiveness of maternal immunization with pertussis vaccines. Tdap is safe and well tolerated in pregnant women. Local and systemic reactogenicity is similar to that observed in nonpregnant adults, and no serious adverse events have been attributed to Tdap vaccination during pregnancy. Maternal antibodies elicited by the vaccine are efficiently transferred to the fetus through the placenta, and studies have consistently found that infants born to vaccinated mothers have significantly higher concentrations of pertussis antibodies than infants of nonvaccinated mothers. Although a correlate of protection against pertussis is unknown, higher concentrations of antibodies are likely to result in protection of young infants. A reduc- tion in infant pertussis has been shown to occur when high vaccine coverage rates are achieved by pregnant women, as reported in the UK vaccination program. Furthermore, as more vaccine programs incorporate Tdap vaccination during pregnancy, prospective and epidemiologic data will be available to continuously assess the safety and efficacy of this intervention. Improving the uptake of pertussis vaccine among pregnant women remains a challenge that will require the joint effort of multiple stakeholders to improve education, access, and acceptability of the vaccine among pregnant mothers and providers.