Association of COVID-19 vaccinations with osteoarthritis flares: A case-crossover study

Objective: People with osteoarthritis (OA) commonly experience flares. Whether COVID-19 vaccination triggers OA flares is unknown. Design: Adults with OA enrolled in a COVID-19 Rheumatology Registry were invited to participate in a casecrossover study. Vaccine data were ascertained from self-report and electronic health records (EHR). OA was identified using coding algorithms and validated via EHR. Participants reported flare and non-flare periods. Vaccine exposures in the 2-, 7-, and 14-day "lookback windows" prior to OA flares were compared to vaccine exposures during similar non-flare ("control") periods. Results: 279 participants had validated OA, and 136 (49%) contributed at least one flare and one control period. Mean age was 68 years [SD +/- 8], 82% female, 87% White, 62% knee OA, 56% hip OA, 37% hand/wrist OA and 60% had > = one anatomic location of OA. 525 COVID-19 vaccine doses were recorded, and participants reported 374 OA flares: 30% were mild, 55% were moderate, and 14% were severe. OA flares were not associated with COVID-19 vaccination 2 or 7 days prior (odds ratios [OR] 0.69 [95% confidence interval (CI): 0.28, 1.66], OR 0.54 [95% CI: 0.27, 1.07], respectively). In the 14-day lookback window, fewer flares occurred after vaccination (OR 0.57 [95% CI: 0.34, 0.97], p=0.039). Analyses stratified on sex, age, knee or hand OA, vaccine brand, and dose showed no increased association between COVID-19 vaccination and OA flares. Conclusion: The lack of positive association between COVID-19 vaccination and OA flare in any primary or secondary analysis provides reassurance regarding the use of COVID-19 vaccines in people with OA. (c) 2025 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.