1. Surveillance of adverse events after diphtheria-tetanus-acellular pertussis (DTaP) vaccine administration reported to the Vaccine Adverse Event Reporting System (VAERS) between 1991 and 2016 revealed no new or unexpected adverse events.
2. The vast majority of reported adverse events were non-serious, and local injection site reactions were the most frequently reported events.
Study Rundown: DTaP replaced diphtheria-tetanus-whole-cell pertussis (DTwP) vaccines in the 1990s due to a safer side-effect profile in pre-licensure studies. In this study, investigators sought to characterize post-licensure safety by reviewing all adverse events after DTaP vaccination reported to VAERS at the Centers for Disease Control (CDC) between 1991 and 2016. The vast majority of reported adverse events were coded as non-serious, and the most frequently reported events were injection site reactions and fever. Rates of serious adverse events were consistent with background rates. No new or unexpected adverse events were identified.
The data were drawn from a passive surveillance system, which may be susceptible to under- or overreporting and ascertainment bias. The causality of reported adverse events in this sample cannot be determined. The study is strengthened by its national scope and the length of surveillance. For physicians, these results reaffirm the safety of licensed DTaP vaccines and help inform conversations with patients about potential adverse events.
Study author, Pedro Moro, MD, MPH, speaks to 2 Minute Medicine: Immunization Safety Office, Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention.
“DTaP vaccines protect young children against three serious bacterial diseases – diphtheria, tetanus, and pertussis – that can cause permanent damage or death. The vaccines are recommended by the Advisory Committee on Immunization Practices and CDC, and their safety is a priority.
Through this study, post-licensure surveillance of adverse events (AEs) for the five licensed DTaP vaccines using the Vaccine Adverse Event Reporting System (VAERS) over a 19-year-period (1991-2016) did not find any new or unexpected safety concerns. These results provide additional reassurance of the safety of DTaP vaccines to both healthcare providers and parents.”
In-Depth [passive surveillance study]: Investigators searched the Vaccine Adverse Event Reporting System (VAERS) of the CDC for all reports of adverse events after DTaP vaccination in the United States between 1991 and 2016. Reports were classified as serious if they involved death, life-threatening illness, hospitalization or prolongation of existing hospitalization, or permanent disability. Disproportionality analysis was conducted to identify adverse events reported more frequently than expected.
A total of 50 157 reports were made to VAERS during the study period. DTaP vaccines were administered concomitantly with other vaccines in 87.7% of reports. A majority, 88.8%, of reports were coded as non-serious. The most frequently reported events were injection site erythema (25.3%), pyrexia (19.8%), injection site swelling (15.0%), erythema (11.2%), and injection site warmth (9.6%). Among the 725 death reports for which medical records were obtained, 48.3% were due to sudden infant death syndrome. Nine adverse events were reported more frequently than expected based on disproportionality analysis, all of them related to injection site reactions. Disproportionality analysis revealed no new or unexpected adverse events.
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