Incidence of stroke following COVID-19 vaccination: a nationwide self‑controlled risk interval study in Qatar

Background: This study assessed short-term stroke risk following COVID-19 vaccination using Qatar’s national stroke registry and health platform. Research design and methods: A self-controlled risk-interval study was conducted among individuals with stroke post-COVID-19 vaccination between 1 December 2020, and 11 April 2023. Stroke incidence during risk windows (0–21 and 22–42 days post-vaccination) was compared to a control window (43–180 days). Results: Among 3,070 stroke cases, 685 met inclusion criteria. Stroke incidence was elevated in the 0–21-day window (IRR: 1.32; 95% CI: 1.07–1.63), but not in the 22–42-day window (IRR: 1.03; 95% CI: 0.82–1.30). Excess risk was estimated at 0.55 (95% CI: −0.04 to 1.01) strokes per 100,000 vaccine doses. IRRs for the 0–21-day window were 1.39 (95% CI: 1.08–1.80) for BNT162b2 and 1.15 (95% CI: 0.78–1.69) for mRNA-1273. By subtype, IRRs were 1.34 (95% CI: 1.07–1.68) for ischemic stroke, 1.11 (95% CI: 0.58–2.11) for hemorrhagic stroke, and 1.46 (95% CI: 0.38–5.56) for cerebral venous sinus thrombosis. Conclusion: A small, transient increase in stroke incidence was observed within 21 days of vaccination; however, such events remain exceedingly rare, with an estimated excess risk substantially lower than that typically associated with infection.