Pertussis Vaccine Safe During Pregnancy

A new study led by Dr. Elyse Kharbanda of the HealthPartners Institute for Education and Research suggests that pertussis (whooping cough) vaccines are safe for women and infants during pregnancy. The study recommends that pregnant women get the tetanus-diphtheria-pertussis (Tdap) vaccine between 27 and 36 weeks gestation to provide the greatest protection from pertussis for the infant.

Pertussis vaccines (Dtap) are also available for children two months and older. The immune systems of younger infants are too delicate to handle the vaccine, and they must rely on antibodies provided by their mother while in the womb. Without the mother’s antibodies or a vaccination, infants are susceptible to many illnesses, not the least of which is whooping cough.

To conduct the study, researchers gathered data from over 123,000 women whose pregnancies ended in live birth from 2010-12. One out of every five of those women received a Tdap vaccination during pregnancy. Low birth rates and pre-term delivery rates among women who had and had not received the vaccine varied minimally, suggesting that the vaccine was safe. Low birth weight was observed in 8.4 percent of mothers who received a Tdap vaccination and 8.3 percent among mothers who had not, according to the study.

Women vaccinated at 36 weeks actually presented lower rates of pre-term delivery than unvaccinated women. The study also found that the mothers who were vaccinated did not report a higher instance of preeclampsia or other blood pressure problems. The women did face slightly higher rates of fetal membrane inflammation, which is caused by the bacterial infection, Chorioamnionititis. However, the main risk of fetal membrane inflammation is premature delivery, which the study showed was not more likely among those who received a Tdap vaccination, according to Kharbanda. These findings suggest that pertussis vaccinations are not only safe, but beneficial for both mother and fetus, especially during the third trimester of pregnancy.

The Centers for Disease Control and Prevention (CDC) reported nearly 50,000 cases of pertussis in 2012, the highest number of cases since 1955. That year, there were 20 deaths related to whooping cough, most of them among infants under three months of age. The CDC reported a decline in cases in 2013, with about 28,600 cases of pertussis in the United States. Infants are more susceptible to whooping cough than any other age group, with children age 7-10 having the second highest incidence. Between Jan. 1 and Aug. 16, 2014, there were 17,300 reported cases, which represents an increase in cases in the U.S. of about 30 percent compared to 2013.

The CDC has suggested that mothers should take the tetanus-diphtheria-pertussis vaccine during the third trimester of pregnancy to safely provide infants with the necessary antibodies to withstand the first two months after birth without antibodies of their own. The two vaccines—Tdap and Dtap—differ in dosage for adults and children. The upper-case “T” denotes a full-strength dose of the tetanus vaccine, and the upper-case “D” denotes a higher dosage of the diphtheria vaccine. Kharbanda has suggested that mothers receive the vaccine during every pregnancy, as antibodies can decrease with time.

By Sree Aatmaa Khalsa

Photo by: Tatiana Vdb – Flickr License
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