Tdap vaccination during pregnancy following other recent tetanus-containing vaccine

Among women who received the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine during pregnancy, there was no increased risk of adverse events in the mothers or adverse birth outcomes in newborns for women who had received a tetanus-containing vaccine in the previous 5 years, according to a study in the October 20 issue of JAMA.

Pertussis (whooping cough) is a vaccine-preventable illness that has been increasing in incidence over the past decade in the United States. Neonates (a baby from birth to four weeks) and infants are at increased risk of pertussis-related hospitalization and death compared with older children and adults. The Advisory Committee on Immunization Practices recommends the Tdap vaccine for pregnant women during each pregnancy, regardless of prior immunization status. However, safety data on repeated Tdap vaccination in pregnancy has been lacking, according to background information in the article.

Lakshmi Sukumaran, M.D., M.P.H., of the Centers for Disease Control and Prevention, Atlanta, and colleagues conducted a study that included 29,155 pregnant women, ages 14 through 49 years, using data from 2007 to 2013 from 7 Vaccine Safety Datalink sites in California, Colorado, Minnesota, Oregon, Washington, and Wisconsin. The authors examined outcomes for women who received Tdap in pregnancy following a prior tetanus-containing vaccine less than 2 years before, 2 to 5 years before, and more than 5 years before.

The researchers found no significant differences in rates of acute adverse events in the mothers (fever, allergy, and local reactions) or adverse birth outcomes in neonates (small for gestational age, preterm delivery, and low birth weight) when comparing women who were vaccinated with Tdap during pregnancy regardless of the length of time since a prior tetanus-containing vaccine.

"Our findings should reassure patients and clinicians who might be hesitant to give Tdap vaccine to pregnant women who recently received a Tdap or other tetanus-containing vaccination," the authors write.

The researchers add that future studies are needed to determine if there are differences in other important adverse pregnancy outcomes, such as stillbirth and spontaneous abortion, when Tdap is given in pregnancy in close intervals from prior tetanus-containing vaccines.