Efficacy of Non-Enhanced Brain Computed Tomography in Patients Presenting to the Emergency Department with Headache after COVID-19 Vaccination.

Headaches are a common side effect of vaccination against the severe acute respiratory syndrome, coronavirus 2; however, it is usually not necessary to seek emergency medical attention or undergo brain imaging such as non-enhanced brain computed tomography (CT) for routine evaluation of vaccine-related headaches. This study aimed to demonstrate that brain CT is of no clinical benefit to patients presenting to the emergency department (ED) with post-coronavirus disease 2019 (COVID-19) vaccination headaches. This retrospective, single-center observational study used electronic medical record (EMR) data of patients who received the COVID-19 vaccination during the first year of the vaccination program. In total, 914 patients were analyzed, of whom 435 underwent CT (CT group, n = 435; no CT group, n = 475). More female patients visited the ED, and there was no significant sex difference between the CT and no-CT groups. The type of vaccine affected the clinical decision to perform brain CT, but the number of doses did not. The CT rate was relatively high for patients who had received the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) and Johnson and Johnson Janssen (Jansen) vaccines ( p = 0.004). Focal neurological deficits were present in all cases of abnormalities on non-enhanced brain CT in patients complaining of headaches. Two out of the 435 patients had abnormal brain CT findings (glioblastoma and Rathke's pouch cyst) at 35 and 32 days after vaccination, respectively. Non-enhanced brain CT should be performed cautiously in patients visiting the ED for post-vaccination headaches only.