News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd
May 16, 2008 — The Advisory Committee on Immunization Practices (ACIP) has issued guidelines on the prevention of pertussis, tetanus, and diphtheria in pregnant and postpartum women and their infants. The new guidelines are published in the May 14 issue of Morbidity & Mortality Weekly Report.
In the United States in 2005, 2 tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines were licensed and recommended for use in adults and adolescents. Adacel (sanofi pasteur) is licensed for use in persons aged 11 to 64 years, and Boostrix (GlaxoSmithKline Biologicals) is licensed for use in persons aged 10 to 18 years.
“Both Tdap vaccines are licensed for single-dose use to add protection against pertussis and to replace the next dose of tetanus and diphtheria toxoids vaccine [Td]),” write Trudy V. Murphy, MD, from the Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and colleagues. “Available evidence does not address the safety of Tdap for pregnant women, their fetuses, or pregnancy outcomes sufficiently. Available data also do not indicate whether Tdap-induced transplacental maternal antibodies provide early protection against pertussis to infants or interfere with an infant’s immune responses to routinely administered pediatric vaccines.”
While awaiting additional data, the ACIP recommends the following for pregnant women who were not previously vaccinated with Tdap:
- Women may receive Tdap shortly after delivery, before discharge from the hospital or birthing center.
- Women may receive Tdap at an interval as short as 2 years since the most recent Td vaccine.
- When indicated, women may receive Td during pregnancy for tetanus and diphtheria protection.
- If the woman is likely to have sufficient protection against tetanus and diphtheria, she may defer the Td vaccine indicated during pregnancy and substitute the Tdap vaccine in the immediate postpartum period.
Tdap vaccine is not contraindicated during pregnancy, but healthcare providers are advised to weigh the theoretical risks and benefits before deciding to administer Tdap vaccine to a pregnant woman.
The guidelines describe the clinical presentation of pertussis, tetanus, and diphtheria in pregnant and postpartum women and their infants; review available data regarding pertussis vaccination during pregnancy as a strategy to prevent infant pertussis; summarize Tdap vaccination policy in the United States; and offer recommendations for use of Td and Tdap vaccines in pregnant and postpartum women.
Some of the specific recommendations follow:
- For women who have not received Tdap previously, the vaccine should be given as soon as is feasible in the immediate postpartum period, preferably before discharge from the hospital or birthing center.
- To lower the risk that women will expose their infants to pertussis, an interval as short as 2 years between the most recent Td and administering Tdap is recommended for postpartum women.
- The dose of Tdap (or of Td, if indicated) is 0.5 mL given intramuscularly, preferably into the deltoid muscle.
- If 2 or more vaccines are indicated, they should be administered during the same visit, but using a separate syringe at a different anatomic site.
- A single dose of Adacel may be given to adults aged 19 to 64 years. Regardless of the type or manufacturer of pediatric diphtheria and tetanus toxoids and whole-cell pertussis or pediatric Tdap vaccine used for childhood vaccination, a single dose of either Adacel or Boostrix may be given to adolescents aged 11 to 18 years.
- Proper immunization technique (eg, use of appropriate needle length and standard routes of administration) may minimize the risk for adverse events.
- Women of childbearing age who might become pregnant and who have not already received Tdap are encouraged to receive a single dose of Tdap either as Adacel (aged 11 – 64 years) or as Boostrix (adolescents aged 11 – 18 years) before conception.
- The risk for pertussis death and severe pertussis is highest among infants in the first months of life and remains elevated until an infant has received 1 to 2 doses of pediatric Tdap.
- Healthcare providers who decide to administer Tdap to pregnant women should first inform their patient of the potential risks and benefits of immunization, including the lack of data on Tdap administered during pregnancy or its unknown effects on active immunization of the infant.
“As with most inactivated vaccines and toxoids, pregnancy is not a contraindication for use of Tdap,” the guidelines authors write. “Although the safety and immunogenicity of Tdap is expected to be similar in pregnant and nonpregnant women, few data on the safety of Tdap for women, fetuses, and pregnancy outcomes are available, and no information is available on the immunogenicity of Tdap in pregnant women. Vaccinating pregnant women with a single dose of Tdap might provide a degree of protection against pertussis to the infant in early life through transplacental maternal antibody, but evidence supporting this hypothesis is lacking.”
MMWR Morb Mortal Wkly Rep. 2008;57:1-47.