Results from a study conducted by researchers from the University of North Carolina (UNC) School of Medicine indicate that women who received the tetanus, diphtheria, acellular pertussis (Tdap) vaccine during pregnancy passed immunity on to their unborn infants. Furthermore, the immunity protected the infants during the early stages of life, closing the gap of vulnerability between birth and the first DTaP vaccination at 2 months of age.
This was the third and final study in a series assessing the safety and effectiveness of Tdap vaccine during pregnancy conducted by UNC. The study was the first to examine the clinical outcomes of the vaccine in infants throughout the first 18 months of life. The results were published in the American Journal of Preventive Medicine.
According to the US Centers for Disease Control and Prevention (CDC), infants are at higher risk of suffering from pertussis, a severe respiratory infection that is also referred to as whooping cough. Furthermore, infants are more likely to experience serious complications. In fact, the CDC estimates that 50% of infants who get pertussis require hospitalization, and of this population, 1 in 100 infants die.
In this study, researchers from UNC reviewed 675,000 pregnancies in the United States between 2010 and 2014 and tracked hospitalizations and outpatient visits through the first 18 months of the infants’ lives.
According to the authors, infants whose mothers received the Tdap vaccination during pregnancy had a 75% reduction of hospitalizations and a 46% reduction of pertussis cases overall.
The vaccination during pregnancy has caused raised concerns regarding potential birth defects or response to DTaP. However, concerns that infants would have a less effective response to their own vaccination series were refuted by the study; infants did not have a less effective response to the DTaP vaccination series administered during infancy.
“This just adds more fuel to the fire for encouraging women to get Tdap during pregnancy. A lot of women are concerned about vaccines in general, but you really might be harming your baby by not getting this vaccine.” said study author, Sylvia Becker-Dreps, MD, MPH, associate professor in the departments of family medicine in the UNC School of Medicine and epidemiology in the UNC Gillings School of Global Public Health in a statement.
The CDC has consistently recommended that children under the age of 7 receive vaccinations through a series of shots at 2 months, 4 months, and 6 months, followed by 2 booster shots later in childhood. However, in 2013, the CDC recommended that all women receive the Tdap vaccination during the third trimester of pregnancy, between 27 and 36 weeks, to pass immunity on to infants before birth. The study did not observe benefits of the vaccine when women received the vaccination earlier in their pregnancy.
“Our results showed that getting it during the third trimester, but at least two weeks before delivery, is best to optimize the benefits of the vaccine.” Dr Becker-Dreps added.