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A Kaiser Permanente study of more than 80,000 children born over a 4-year period showed that the prenatal Tdap vaccination-tetanus, diphtheria, acellular pertussis was not associated with increased risk of autism spectrum disorder in children.
Infants are at the risk of death among any population subgroup after contracting a pertussis infection, a highly contagious respiratory disease also known as the whooping cough, said Tracy A. Becerra-Culqui, PhD, a post-doctoral research fellow with Kaiser Permanente Southern California’s Department of Research & Evaluation and lead author of the study.
The Advisory Committee on Immunization Practices recommends pregnant women receive the Tdap vaccine to prevent pertussis infection; it is very important for pregnant women to be immunized against pertussis, it is an immunity pass to fetus.
Kaiser Permanente researchers were able to comprehensively study the hypothesized link between Tdap and autism. In Southern California, Kaiser Permanente provides health care in 15 hospitals and about 220 medical offices to approximately 4.4 million members who are broadly representative of the area’s population. Recommended vaccinations are free to all members.
This retrospective cohort study looked at the autism diagnosis for children born at Kaiser Permanente hospitals in Southern California between Jan. 1, 2011 and Dec. 31, 2014. The study included 81,993 children and found that: prenatal Tdap vaccination coverage ranged from 26 percent for the 2012 birth cohort to 79 percent for the 2014 birth cohort.
The autism spectrum disorder incidence rate in children was 1.5 percent in the maternal Tdap vaccinated group and 1.8 percent in the maternal unvaccinated group, comparable to autism rates in the United States (1.7 percent). Analyses of the data extracted from electronic health records showed that Tdap vaccination during pregnancy was not associated with increased autism spectrum disorder risk in children.
Results were consistent across study birth years and among first-born children. The link between vaccination and development of autism has been refuted by many rigorous scientific investigations.