Giant Cell Arteritis After mRNA COVID Vaccines: Concerning Or A False Alarm?-A Retrospective Cohort Study

Background: The coronavirus disease (COVID-19) pandemic led to the first large-scale rapid deployment of novel messenger RNA (mRNA) vaccines. Although the effectiveness and safety of these vaccines were rigorously studied, post-vaccination adverse events such as giant cell arteritis (GCA) continue to be reported. More than two hundred and sixty three cases of new-onset GCA occurring after mRNA vaccine administration are listed in the Vaccine Adverse Events Reporting System as of October 2024. We aimed to explore the incidence of GCA after mRNA vaccines among patients in our health system and study their characteristics and outcomes. Methods: We conducted a retrospective descriptive study from the Rochester Regional Health system, which serves around one million patients in upstate/western New York State. In this region, more than 60% of the eligible adult population have received at least one dose of mRNA vaccine. A data extraction tool for the system’s electronic medical record identified adult patients who received the mRNA COVID vaccine (Pfizer-BioNTech or Moderna) and then developed GCA. Identified patient records were manually reviewed, and only patients that developed GCA within 60 days of mRNA COVID-19 vaccine administration were included in the analysis. Basic demographic characteristics, diagnostic criteria, treatment received, and outcome data were extracted into an Excel spreadsheet. Results: We found 288 COVID 19 vaccinated adults with GCA, but only seven were included in the study based on the inclusion criteria. All these seven patients were female and were older than 50 years (mean age 72 years). Most patients were white, and one was African American. Most patients developed GCA within 30 days of the vaccine administration (5–25 days). The diagnosis of GCA was confirmed with Temporal Artery Biopsy (TAB) in five patients and using other clinical and lab parameters as per ACR/EULAR 2022 criteria in two patients. All patients were started on high dose steroids, Six were transitioned to low dose steroids in addition to steroid sparing agents (methotrexate or tocilizumab). One patient was continued on a chronic low dose steroid alone. Five patients had complete remission and two had partial vision loss. Conclusions: GCA after administration of mRNA vaccine is an extremely rare occurrence, but given the potentially severe consequences, awareness about this adverse event needs to be raised. The baseline characteristics (female, age >50 years, and white) and the visual outcomes in these patients do not seem to be drastically different from other patients with GCA. Further studies are