Pregnant women are targeted for specific vaccines to protect them and their infants. Ongoing monitoring of the safety and effectiveness of vaccinating pregnant women is necessary to reassure the public. Here we describe the establishment of a dynamic database linking mothers to newborns with the goal of studying vaccine safety in both pregnant women and their children and provide results of a pilot study utilizing this database as a proof of concept.
We developed a pregnancy database utilizing various electronic databases within an integrated healthcare system. Women with a visit for a confirmed pregnancy were eligible for inclusion. We used the medical record number (MRN), a unique identifier, to retrieve information about events that occurred during the pregnancy and at delivery, and linked this same MRN to newborns for post-partum follow up. We conducted a pilot cohort study to evaluate the association between receipt of tetanus, diphtheria and acellular pertussis (Tdap) vaccine during pregnancy and fever 0-3 days after the first dose of diphtheria tetanus and acellular pertussis (DTaP) vaccine in the infant. The study included infants who were born at ≥37 weeks gestation from January 1, 2009 – October 1, 2015 and who received their first DTaP vaccine between 6 – 10 weeks of age. We utilized diagnostic codes from inpatient, emergency department, outpatient clinics, and telephone calls. We identified fever using ICD 9 code 780.6, recorded temperature ≥ 101 degree Fahrenheit, or maternal report.