According to the results of a recently published review, administration of extra dose of a vaccine was not associated with the presence of new or unexpected adverse health events (AHEs) or safety issues.

The aim of the study was to determine and characterize the most commonly reported adverse events (AEs) correlated with administration of excess doses of vaccine. Study authors searched the Vaccine Adverse Event Reporting System (VAERS) for patients who were administered an excess dose of vaccine and reviewed all serious reports discussed in their medical records.

Additionally, a random sample of non-serious reports was also reviewed. “The most common AEs among reports of excess dose of vaccine administered were compared with the corresponding AEs for all vaccines reported to VAERS during the same period,” the study authors explained.

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Of the 366,815 VAERS reports received between the study period (Jan 1, 2007 to Jan 26, 2018), 5067 (1.4%) reported administration of an excess dose of vaccine. Vaccines most commonly reported included: trivalent inactivated influenza (15.4%), varicella (13.9%), hepatitis A (11.4%), and measles, mumps, rubella, varicella (11.1%).

The study authors stated that 76.9% (n=3898) of the reports in which an excess vaccine dose was administered did not describe or discuss an AHE. The most common AHEs that were described in the remaining reports included pyrexia (12.8%), erythema at the injection site (9.7%), pain at the injection site (8.9%), and headache (6.6%). “The percentage of AHEs among these reports was comparable to all reports submitted to VAERS during the same study period,” the study authors stated.

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Based on their findings, the authors concluded that the administration of an excess dose of vaccine was not associated with any new or unexpected safety issues. They added, “These reports occurred due to diverse vaccination errors, typically programmatic errors many of which should have been avoided by greater awareness of the administration instructions for the vaccines being administered or increased awareness of the immunization history of the patient.”

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This article originally appeared on MPR