Giant Cell Arteritis Following COVID-19 Vaccination: A Consumer-Stimulated Analysis

INTRODUCTION: Giant cell arteritis (GCA) is an immune-mediated vasculitis of large and medium arteries, mainly affecting older adults. Prompted by a consumer concern, a few spontaneous reports after coronavirus disease 2019 (COVID-19) vaccination and Australian regulator signal, we investigated a possible association between GCA and vaccination. METHODS: This study analysed multiple data sources from January 2021 to September 2024. We reviewed spontaneous GCA reports submitted to the statewide vaccine safety service, Surveillance of Adverse Events following Vaccination in the Community (SAEFVIC), and applied self-controlled case series (SCCS) to two large Australian healthcare datasets [general practice (GP) and linked hospital data]. SCCS used a 1-42-day risk window, stratified by vaccine type, age, and sex. Incident GCA cases were identified via keyword matching and diagnostic codes [Systematized Nomenclature of Medicine Clinical Terms (SNOMED-CT)/International Classification of Diseases Tenth Revision, Australian Modification (ICD-10-AM)]. RESULTS: Six cases of GCA were spontaneously reported, four with onset within 42 days postvaccination, all following the adenoviral vectored Vaxzevria® {reporting rate 0.10 [95% confidence interval (CI) 0.03-0.27]}. The proportional reporting ratio signal detection method did not indicate a safety signal. Of 2700 incident cases of GCA identified across primary and hospital care datasets, 293 occurred within 42 days of COVID-19 vaccination. There was no increased risk of GCA following COVID-19 vaccination in either dataset [GP relative incidence (RI): 0.96 (95% CI 0.76, 1.21); hospital RI: 0.79 (95% CI 0.68, 0.91)], including by vaccine type, age, or sex. CONCLUSIONS: Using three Australian data sources, this study found no increase in GCA presentations within 6 weeks of COVID-19 vaccination. These consumer-stimulated findings support informed decisions, strengthen vaccine safety evidence, and help clinicians counsel patients.