Tdap for Pregnant Women: Information for Providers
For Healthcare Professionals
In October 2012, the Advisory Committee on Immunization Practices (ACIP) voted to recommend that healthcare personnel should administer a dose of Tdap during each pregnancy irrespective of the patient's prior history of receiving Tdap (or Td). To maximize the maternal antibody response and passive antibody transfer to the infant, optimal timing for Tdap administration is between 27 and 36 weeks gestation. This recommendation is supported by the American College of Obstetricians and Gynecologists (ACOG) and the American College of Nurse-Midwives [4 pages].
The United States is experiencing a resurgence of pertussis. Since 2010, we see between 10,000 and 50,000 cases of pertussis each year and cases are reported in every state. In 2012, we saw the most cases we had seen in 60 years. There were 48,277 reported cases of pertussis; 2,269 of those cases were in infants younger than 3 months of age — 15 of those infants died.
Pertussis can cause serious and sometimes life-threatening complications in infants, especially within the first 6 months of life. In infants younger than 1 year of age who get pertussis, about half are hospitalized. The younger the infant, the more likely treatment in the hospital will be needed. Of those infants who are hospitalized with pertussis, about 67% will have apnea, 23% will get pneumonia, and 1.6% will die.
In recent years, up to 1,450 infants have been hospitalized due to pertussis and about 10 to 20 die each year in the United States. Most pertussis deaths are infants who are too young to be protected by the childhood pertussis vaccine (DTaP).
Adolescents and adults can also experience complications from pertussis. Complications are usually less serious in this age group, especially in those who have been vaccinated. Common complications in adolescents and adults are often caused by the cough itself, including urinary incontinence (28%), syncope (6%), and rib fractures (4%).
Three key strategies are recommended to protect infants from pertussis:
- Administering Tdap vaccine to women during every pregnancy
- Encouraging close contacts of infants to be up-to-date with their pertussis vaccine (cocooning)
- Vaccinating infants with DTaP according to the childhood immunization schedule
Transfer of Pertussis Antibodies to Infant through Maternal Tdap Vaccination
Transplacental transfer of maternal pertussis antibodies from mother to infant provides some protection against pertussis in early life, before infants are able to receive the primary DTaP series. Since the immune response to the vaccine peaks about 2 weeks after administration, Tdap vaccine is recommended between 27 and 36 weeks gestation in order to optimize antibody transfer and protection at birth. The level of pertussis antibodies decreases over time, so Tdap vaccine should be administered during every pregnancy so that each infant receives high levels of protective antibodies.
New studies suggest that postpartum immunization is not effective in reducing pertussis illness in infants 6 months of age or younger. Ideally, pregnant women should be vaccinated with Tdap during pregnancy to help prevent more infant hospitalizations and deaths from pertussis than would be prevented by postpartum vaccination. The only time a woman should be administered the vaccine postpartum is if she has never received Tdap before.
There are currently no pertussis vaccines licensed or recommended for newborns at birth. The best way to prevent pertussis in a young infant is by vaccinating the mother during pregnancy, encouraging people around the infant to be up-to-date with their pertussis vaccine, and administering the childhood DTaP series on schedule.
Both CDC and FDA monitor vaccine safety through the Vaccine Adverse Event Reporting System (VAERS), a national vaccine safety surveillance program. Published studies that include VAERS data support the safe use of Tdap vaccine during pregnancy. To date, no safety signals have been found among pregnant women or their babies after Tdap vaccination.
Both tetanus and diphtheria toxoids (Td) and tetanus toxoid (TT) vaccines have been used extensively in pregnant women worldwide since the 1960s to prevent neonatal tetanus. Td and TT vaccines administered during pregnancy have not been shown to harm either the mother or baby/fetus.
See the Pregnancy and Whooping Cough Research page for a list of published articles specific to preventing pertussis in infants, including safety studies.
Most side effects from Tdap vaccination are mild or moderate, and self-resolving. The most common side effects include erythema, swelling, pain, and tenderness at the injection site, body-ache, fatigue, or fever. Severe side effects are extremely rare, especially in adults.
CDC and ACOG consider the benefits of Tdap vaccination in multiple pregnancies to outweigh the theoretical risk for severe hypersensitivity due to administering the tetanus component of the Tdap vaccine more often (see ACOG's Committee Opinion). Studies found that adults who receive 2 tetanus shots in a short period of time (within 2 years) were no more likely than adults getting their first Tdap vaccine to have severe side effects. Experts believe the risk for this type of severe side effect has likely been reduced since these vaccines are now made with lower doses of the tetanus component than tetanus vaccines in the past.
Breastfeeding is not a contraindication for receiving Tdap vaccine and is, in fact, fully compatible with Tdap vaccination. Tdap vaccine can and should be given to women who plan to breastfeed.
Pertussis and flu vaccines can safely be coadministered to pregnant women. Pregnant women should receive the flu vaccine as early as possible in the flu season, during any trimester, while the pertussis vaccine is recommended later in pregnancy (between 27 and 36 weeks gestation).
None of the pertussis vaccines (Tdap and DTaP) currently used in the United States contain thimerosal.
Early evidence shows that young infants whose mothers were vaccinated with Tdap during pregnancy are less likely to develop pertussis during the first few critical months of life. One study from the United Kingdom suggests that up to 90% of infants are protected against whooping cough by vaccination of their mother during pregnancy.
Since pregnant women pass some protection to their infants through transplacental transfer of maternal antibodies, their infants also have some protection against the severe outcomes that come with this disease. It is critical that infants receive the childhood DTaP series on schedule so protection is maintained throughout childhood.
By vaccinating a woman with Tdap during pregnancy her infant will gain pertussis antibodies during the most vulnerable time - before 3 months of age. Providing this early immunity may interfere with the infant's immune response to DTaP vaccine though. The infant's immune response to DTaP may not be as strong; however, based on a recent study looking at this issue, this interference does not seem to cause any problems when it comes to protecting infants. Researchers are still working to better understand this issue.
The benefits of vaccinating during pregnancy and protecting a newborn outweigh the potential risk of blunting the infant's response to DTaP vaccine. Since infants are at greatest risk of severe disease and death from pertussis before 3 months of age – when their immune systems are least developed – any protection that can be provided is critical. Infants should receive their DTaP vaccines on schedule, starting at 2 months of age.
CDC's current estimate is that Tdap vaccination protects against pertussis in about 70% of people who receive it, but that protection fades over time. The long-term effectiveness of Tdap is still being studied. Adolescents and adults who get Tdap and still get pertussis have fewer coughing fits, shorter illness, and are less likely to suffer from disease complications.
DTaP vaccination is effective for 80%-90% of children who receive it. Among children who get all 5 doses of DTaP vaccine on schedule, effectiveness is very high within the year following the 5th dose — nearly all children (98%) are fully protected. More is known about the long-term effectiveness of DTaP. In general, there is a modest decrease in effectiveness in each year following the last dose. About 70% of children are fully protected 5 years after getting their last dose of DTaP and the other 30% are protected against serious disease.
The strategy of protecting infants from pertussis by vaccinating those in close contact with them is known as "cocooning." ACIP has recommended cocooning with Tdap vaccine since 2005 and continues to recommend this strategy for all those with expected close contact with infants younger than 1 year of age. Cocooning, in combination with maternal Tdap vaccination and administering the childhood DTaP series on schedule, provides the best protection to the infant.
In addition to vaccinating your patients with Tdap, you should educate them about encouraging others – including dads, grandparents and other caregivers – to be up-to-date with pertussis vaccination. For family members who aren't up-to-date with Tdap vaccine, they should get vaccinated at least 2 weeks before coming into contact with the infant.
Full implementation of cocooning has proven to be a challenge; vaccinating during pregnancy provides the best opportunity to protect very young infants from pertussis.
It is very important for infants to get their own pertussis vaccine (DTaP) according to the childhood schedule so they can start building their own protection against the disease. The primary series is administered at 2, 4, and 6 months to build up high levels of protection. Booster shots are administered at 15 through 18 months and at 4 through 6 years to maintain that protection.
See the Pregnancy and Whooping Cough Research page for a list of published articles specific to preventing pertussis in infants, including safety studies and immunization recommendations.