The overwhelming majority of morbidity and mortality attributable to pertussis infection occurs in infants who are 3 months and younger. Infants do not begin their own vaccine series against pertussis until approximately 2 months of age. This leaves a window of significant vulnerability for newborns, many of whom contract serious pertussis infections from family members and caregivers, especially their mothers, or older siblings, or both. In 2013, the Advisory Committee on Immunization Practices published its updated recommendation that a dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) should be administered during each pregnancy, irrespective of the prior history of receiving Tdap.
New data demonstrate that immunizing against Tdap early within the 27–36 weeks of gestation window maximizes the maternal antibody response and passive antibody transfer to the fetus. Therefore, giving the Tdap vaccine as early as possible in the 27–36-weeks-of-gestation window appears to be the best strategy. Linking the Tdap vaccination to screening for gestational diabetes will allow this to be implemented easily. For women who are Rh negative, another strategy worth consideration is to administer Tdap vaccination during the same visit as Rho(D) immune globulin administration. Since protection from previous vaccination is likely to decrease over time, a Tdap vaccination is necessary during every pregnancy to give the best possible protection to the newborn.
For women who have never received a prior dose of Tdap, if Tdap was not administered during pregnancy, it should be administered immediately postpartum in order to reduce the risk of transmission to the newborns. A woman who did not receive the Tdap vaccine during her most recent pregnancy, but received it previously as an adolescent, adult, or during a prior pregnancy should not receive Tdap postpartum.
Given the rapid evolution of data surrounding this topic, immunization guidelines are likely to change over time, and the American College of Obstetricians and Gynecologists (ACOG) continues to issue updates accordingly. ACOG makes the following recommendations in its committee opinion “Update on Immunization and Pregnancy: Tetanus, Diphtheria, and Pertussis Vaccination“ (Number 718, September 2017):
- Obstetric care providers should administer the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine to all pregnant patients during each pregnancy, as early in the 27–36 weeks of gestation window as possible.
- Pregnant women should be counseled that the administration of the Tdap vaccine during each pregnancy is safe and important to make sure that each newborn receives the highest possible protection against pertussis at birth.
- Obstetrician–gynecologists are encouraged to stock and administer the Tdap vaccine in their offices.
- Partners, family members, and infant caregivers should be offered the Tdap vaccine if they have not previously been vaccinated. Ideally, all family members should be vaccinated at least 2 weeks before coming in contact with the newborn.
- If not administered during pregnancy, the Tdap vaccine should be given immediately postpartum if the woman has never received a prior dose of Tdap as an adolescent, adult, or during a previous pregnancy.
- There are certain circumstances in which it is appropriate to administer the Tdap vaccine outside of the 27–36 weeks of gestation window. For example, in cases of wound management, a pertussis outbreak, or other extenuating circumstances, the need for protection from infection supercedes the benefit of administering the vaccine during the 27–36 weeks of gestation window.
- If a pregnant woman is vaccinated early in her pregnancy (i.e., before 27–36 weeks of gestation), she does not need to be vaccinated again during 27–36 weeks of gestation.
ACOG recommends routine assessment of each pregnant woman’s immunization status and administration of indicated immunizations. Importantly, evolving data demonstrate maternal and neonatal protection against an increasing number of aggressive newborn pathogens through the use of maternal immunization, suggesting pregnancy is an optimal time to immunize for disease prevention in women and newborns.
There is no evidence of adverse fetal effects from vaccinating pregnant women with an inactivated virus or bacterial vaccines or toxoids, and a growing body of robust data demonstrate safety of such use. Concomitant administration of indicated inactivated vaccines during pregnancy (i.e., Tdap and influenza) is also acceptable, safe, and may optimize effectiveness of immunization efforts. Furthermore, no evidence exists that suggests that any vaccine is associated with an increased risk of autism or adverse effects due to exposure to traces of the mercury-containing preservative thimerosal. The Tdap vaccines do not contain thimerosal. The benefits of inactivated vaccines outweigh any unproven potential concerns. It is important to remember that live attenuated vaccines (e.g., measles–mumps–rubella [MMR], varicella, and live attenuated influenza vaccine) do pose a theoretical risk (although never documented or proved) to the fetus and generally should be avoided during pregnancy.
All vaccines administered during pregnancy as well as health care provider-driven discussions about the indications and benefits of immunization during pregnancy should be fully documented in the patient’s prenatal record. In addition, if a patient declines vaccination, this refusal should be documented in the patient’s prenatal record, and the health care provider is advised to revisit the issue of vaccination at subsequent visits.
Pregnant women who live in geographic regions with new outbreaks or epidemics of pertussis should be immunized as soon as feasibly possible for their own protection in accordance with local recommendations for nonpregnant adults. In these acute situations, less emphasis should be given to targeting the proposed optimal gestation window (between 27 weeks and 36 weeks of gestation) given the imperative to protect the woman from locally prevalent disease. Newborn protection will still be garnered from vaccination earlier in the same pregnancy. Importantly, a pregnant woman should not be revaccinated later in the same pregnancy if she received the vaccine in the first or second trimester.
As part of standard wound management care to prevent tetanus, a tetanus toxoid-containing vaccine is recommended in a pregnant woman if 5 years or more have elapsed since her previous tetanus and diphtheria (Td) vaccination. If a Td booster vaccination is indicated in a pregnant woman for acute wound management, the obstetrician–gynecologist or other health care provider should administer the Tdap vaccine, irrespective of gestational age. A pregnant woman should not be revaccinated with Tdap in the same pregnancy if she received the vaccine in the first or second trimester.
Indicated Tetanus and Diphtheria Booster Vaccination:
If a Td booster vaccination is indicated during pregnancy (i.e., more than 10 years since the previous Td vaccination) then obstetrician–gynecologists and other health care providers should administer the Tdap vaccine during pregnancy within the 27–36 weeks of gestation window. This recommendation is because of the nonurgent nature of this indication and the desire for maternal immunity. It also will maximize antibody transfer to the newborn.
Unknown or Incomplete Tetanus Vaccination:
To ensure protection against maternal and neonatal tetanus, pregnant women who have never been vaccinated against tetanus should begin the three-vaccination series, containing tetanus and reduced diphtheria toxoids, during pregnancy. The recommended schedule for this vaccine series is at 0 weeks, 4 weeks, and 6–12 months. The Tdap vaccine should replace one dose of Td, preferably given between 27 weeks and 36 weeks of gestation.
The Advisory Committee on Immunization Practices recommends that all adolescents and adults who have or who anticipate having close contact with an infant younger than 12 months (e.g., siblings, parents, grandparents, child care providers, and health care providers) who previously have not received the Tdap vaccine should receive a single dose of Tdap to protect against pertussis and reduce the likelihood of transmission. Ideally, these adolescents and adults should receive the Tdap vaccine at least 2 weeks before they have close contact with the infant.