Prenatal Healthcare

Mamas on Bedrest: New Recommendations for Tetanus, Diphtheria, Pertussis Vaccination During Pregnancy

October 26th, 2012

On October 24, 2012, The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention voted unanimously to recommend that all pregnant women receive a Tetanus, Diphtheria, Pertussis (Tdap) Vaccination during pregnancy. Additionally, ACIP recommends that all women receive a Tdap during each and every pregnancy.

Vaccinations in the United States are controversial. Vaccination during pregnancy is extremely controversial because of the concern of harm to the unborn child. However, ACIP has found that the risk of newborn infants developing pertussis (whooping cough) greatly outweighs any risk of severe adverse reactions to mama or unborn child receiving the Tdap vaccine.

According to Jennifer Liang, MD, from the CDC National Center for Immunization and Respiratory Diseases, who presented the proposed changes during the ACIP meeting in Atlanta, Georgia,

“Although there are no data to address what we really want to know [the potential for severe adverse events associated with repeat vaccinations for pregnant women who have multiple pregnancies in a short time interval], the data from studies in which healthy adults received 2 doses of Tdap are reassuring, and the historical experience with tetanus toxoid vaccine suggests no excess risk of adverse events with multiple doses.”

What is known is that infants that develop pertussis under two months of age have a much higher rate of complications and are at greater risk of death from the disease. It was previously believed that if Mama was up to date with her vaccinations, then baby would be okay. What the ACIP workgroup found is that many women are unsure of their immunization status or they had their Tdap vaccines so long ago (while still within the 10 yr window of “normal” for adults) that transferal of immunity to there babies was minimal if at all. Initially the CDC recommended that women who were unsure of their vaccine status receive Tdap, but now, given current data, they are recommending that all pregnant women receive Tdap during pregnancy between 27 and 36 weeks gestation.

The biggest change to their recommendations is that ACIP recommends that women have Tdap vaccines with all subsequent pregnancies. Based upon a review of published and unpublished studies on the use of Tdap in pregnant women and Tdap safety data from pregnancy registries and the Vaccine Adverse Event Reporting System, the ACIP Pertussis Vaccine Work Group concluded

“A single dose of Tdap at one pregnancy was insufficient to provide protection for subsequent pregnancies and that the benefits of vaccination outweigh the theoretical risks of severe adverse events.”

The work group found that since most women in the US have no more than 2-3 pregnancies, and given the safety and efficacy of Tdap, the additional doses of vaccine (theoretically) pose no threat to Mamas. (I was wondering if multiple doses of Tdap were safe for women who have pregnancies close together, i.e. children born 13 months apart. But given that infants receive multiple doses of a similar vaccination within the first year, this likely poses no immediate threat to mamas.) The working group supports and recommends continued research and study to definitively assess safety of Tdap administration in multiple (and perhaps close) pregnancies.

Other recommendations include vaccinating women in the immediate post partum if immunization status is unknown or if they were not immunized during pregnancy. ACIP also recommends that the childhood immunization schedules be updated so that teenagers that become pregnant receive Tdap according to this new protocol.

With approval of these recommendations by the US Department of Health and Human Services, they will be published in the 2013 edition of Morbidity and Mortality Weekly Report, the guide routinely referred to by health care providers for the latest recommendations to standards of care.

Resources

MedScape OB/GYN and Women’s Health News

The 2011 ACIP Recommendations for Tdap in Pregnancy