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J Clin Med
. 2026 Jul 13;15(14):5487.
doi: 10.3390/jcm15145487.
Posterior Circulation Ischemic Stroke Occurring After ChAdOx1 nCoV-19/AZD1222 Vaccination Without Evidence of Vaccine-Induced Immune Thrombotic Thrombocytopenia: A Case Report and Focused Narrative Review
Félix Bermejo-Pareja 1 , Cristina Ramo-Tello 2 3 , Julián Benito-León 1 2 3 4
Affiliations
Background: Ischemic stroke has been reported rarely after coronavirus disease 2019 (COVID-19) vaccination, most clearly in association with vaccine-induced immune thrombotic thrombocytopenia (VITT). Nevertheless, temporal proximity alone cannot establish causality, particularly when conventional vascular risk factors are present. We report a case of posterior circulation ischemic stroke occurring 36-48 h after first-dose ChAdOx1 nCoV-19/AZD1222 vaccination without VITT and provide a focused narrative review of the clinical, epidemiological, and mechanistic evidence regarding post-vaccination stroke. Methods: Clinical, laboratory, and neuroimaging data were reviewed retrospectively. A focused narrative literature review was performed to contextualize VITT-related and non-VITT ischemic stroke after COVID-19 vaccination, pharmacovigilance signals, population-based evidence, and proposed biological mechanisms. Results: A 63-year-old man with well-controlled hypertension and a remote history of smoking developed systemic symptoms within 24 h of first-dose ChAdOx1 nCoV-19/AZD1222 vaccination, followed by severe hypertension and acute posterior circulation neurological symptoms 36-48 h after vaccination. Neuroimaging showed an acute left cerebellar infarct extending into the middle cerebellar peduncle, with approximately 50% stenosis of the intradural left vertebral artery. Platelet counts remained normal, D-dimer and anti-PF4 antibody testing were normal, SARS-CoV-2 polymerase chain reaction (PCR) testing was negative, and routine cardiac evaluation did not identify a definite cardioembolic source. Conclusions: This case highlights an early posterior circulation ischemic stroke temporally associated with ChAdOx1 nCoV-19/AZD1222 vaccination in the absence of VITT. Although individual causality cannot be established from a single case, careful reporting of such presentations may improve clinical recognition, etiological evaluation, and pharmacovigilance.
Keywords: AZD1222; COVID-19 vaccination; ChAdOx1 nCoV-19; TOAST classification; VITT; cerebellar infarction; ischemic stroke; narrative review; pharmacovigilance; posterior circulation; temporal association.
. 2026 Jul 13;15(14):5487.
doi: 10.3390/jcm15145487.
Posterior Circulation Ischemic Stroke Occurring After ChAdOx1 nCoV-19/AZD1222 Vaccination Without Evidence of Vaccine-Induced Immune Thrombotic Thrombocytopenia: A Case Report and Focused Narrative Review
Félix Bermejo-Pareja 1 , Cristina Ramo-Tello 2 3 , Julián Benito-León 1 2 3 4
Affiliations
- PMID: 42513402
- PMCID: PMC13412417
- DOI: 10.3390/jcm15145487
Background: Ischemic stroke has been reported rarely after coronavirus disease 2019 (COVID-19) vaccination, most clearly in association with vaccine-induced immune thrombotic thrombocytopenia (VITT). Nevertheless, temporal proximity alone cannot establish causality, particularly when conventional vascular risk factors are present. We report a case of posterior circulation ischemic stroke occurring 36-48 h after first-dose ChAdOx1 nCoV-19/AZD1222 vaccination without VITT and provide a focused narrative review of the clinical, epidemiological, and mechanistic evidence regarding post-vaccination stroke. Methods: Clinical, laboratory, and neuroimaging data were reviewed retrospectively. A focused narrative literature review was performed to contextualize VITT-related and non-VITT ischemic stroke after COVID-19 vaccination, pharmacovigilance signals, population-based evidence, and proposed biological mechanisms. Results: A 63-year-old man with well-controlled hypertension and a remote history of smoking developed systemic symptoms within 24 h of first-dose ChAdOx1 nCoV-19/AZD1222 vaccination, followed by severe hypertension and acute posterior circulation neurological symptoms 36-48 h after vaccination. Neuroimaging showed an acute left cerebellar infarct extending into the middle cerebellar peduncle, with approximately 50% stenosis of the intradural left vertebral artery. Platelet counts remained normal, D-dimer and anti-PF4 antibody testing were normal, SARS-CoV-2 polymerase chain reaction (PCR) testing was negative, and routine cardiac evaluation did not identify a definite cardioembolic source. Conclusions: This case highlights an early posterior circulation ischemic stroke temporally associated with ChAdOx1 nCoV-19/AZD1222 vaccination in the absence of VITT. Although individual causality cannot be established from a single case, careful reporting of such presentations may improve clinical recognition, etiological evaluation, and pharmacovigilance.
Keywords: AZD1222; COVID-19 vaccination; ChAdOx1 nCoV-19; TOAST classification; VITT; cerebellar infarction; ischemic stroke; narrative review; pharmacovigilance; posterior circulation; temporal association.