Ischemic stroke shortly after vaccination against SARS-CoV-2: A case-control study

BACKGROUND AND PURPOSE: Vaccination against SARS-CoV-2 has been associated with rare occurrences of severe venous thromboses. Very little data exist about arterial ischemic strokes. We have assessed the features of ischemic strokes occurring shortly after vaccination against SARS-CoV-2 in the Cremona area, Italy. METHODS: From February 1, to July 31, 2021, all patients with ischemic stroke within four weeks of vaccination against COVID-19 admitted to our stroke unit were consecutively collected, and their main features were compared with those of all other patients with ischemic strokes admitted during the same period. RESULTS: Sixteen strokes after vaccination were collected. They represented 10.5% of all ischemic strokes. Median interval from vaccination was 12 days (range 1–24). Fifteen (93.8%) had received the BNT162b2 (Pfizer–BioNTech) vaccine and 1 (6.2%) the ChAdOx1 nCoV-19 (AstraZeneca). Two patients (12.5%) had a mild thrombocytopenia on admission (128,000 and 142,000/ml), without any evidence of bleeding or venous thrombosis. Thrombolysis and/or thrombectomy were carried out in 4 cases (25.0%). When compared with 137 strokes without recent vaccination, none of the demographic, clinical, and laboratory features of post-vaccination strokes were significantly different. CONCLUSIONS: Ischemic strokes occurring shortly after COVID-19 vaccination at our center were similar to those of non-vaccinated patients. Therefore, the relatively high percentage of such patients probably relates to the very high fraction of elderly people vaccinated against SARS-CoV-2 in the Cremona area, rather than to a consequence of vaccination.