Related Experiment Video
Updated: May 5, 2026
08:47
Intracranial Injection of Adeno-associated Viral Vectors
Published on: November 17, 2010
47.5K
Ischemic Stroke After Bivalent COVID-19 Vaccination: Self-Controlled Case Series Study.
Stanley Xu1, Lina S Sy1, Vennis Hong1
1Department of Research & Evaluation, Southern California Permanente Medical Group, Pasadena, CA, United States.
JMIR Public Health and Surveillance
|June 25, 2024
Summary
Bivalent COVID-19 vaccination did not increase ischemic stroke risk overall. A potential increased risk was observed within 42 days for younger individuals receiving both Pfizer-BioNTech and flu vaccines, warranting further study.
Area of Science:
- Epidemiology
- Vaccinology
- Neurology
Background:
- The association between bivalent COVID-19 vaccines and ischemic stroke risk is not fully understood.
- Existing studies have yielded uncertain conclusions regarding this potential link.
Purpose of the Study:
- To assess the risk of ischemic stroke following bivalent COVID-19 vaccination during the 2022-2023 season.
- Evaluate potential associations in specific subgroups and with coadministered vaccines.
Main Methods:
- A self-controlled case series study design was employed.
- Utilized electronic health records for ischemic stroke identification (ICD-10 codes).
- Analyzed risk intervals of 1-21 and 1-42 days post-vaccination using conditional Poisson regression.
Main Results:
- No increased ischemic stroke risk was found within 21 days for either vaccine.
- An elevated risk was noted within 42 days for individuals under 65 receiving Pfizer-BioNTech and influenza vaccines concurrently.
- Subgroup analyses revealed potential elevated risks in specific populations, though often not statistically significant after chart review.
Conclusions:
- The study found no statistically significant increase in ischemic stroke risk associated with bivalent COVID-19 vaccination overall.
- Further investigation is needed for specific subgroups, particularly younger individuals receiving concurrent influenza vaccination and those with prior SARS-CoV-2 infection.
- Highlights the importance of ongoing vaccine safety surveillance, including for monovalent vaccines in the subsequent season.
Keywords:
COVID-19SARS-CoV-2TIAadverseassociationbivalentbivalent COVID-19 vaccinecardiovascularcase seriescoadministrationcorrelationincidenceinfectiousinfluenzainfluenza vaccineischemiaischemicischemic strokerespiratoryriskrisksself-controlled case seriesside effectstrokesubgroup analysessubgroup analysistransient ischemic attackvaccinationvaccinevaccines
Related Concept Videos
01:17Ischemic Heart Disease: Overview
3.8K
Ischemic heart disease occurs when the heart's blood supply dwindles, causing an ominous lack of oxygen and nutrients. This deficiency, stemming from reduced or obstructed blood flow, spells danger, leading to heart muscle damage and dysfunction.
Atherosclerosis, the primary malefactor, orchestrates this dangerous condition. It manifests as the accumulation of fatty deposits, akin to insidious plaques, within arterial walls. As time elapses, these plaques metamorphose, hardening and...
Atherosclerosis, the primary malefactor, orchestrates this dangerous condition. It manifests as the accumulation of fatty deposits, akin to insidious plaques, within arterial walls. As time elapses, these plaques metamorphose, hardening and...
3.8K
01:15Ischemic Stroke l: Introduction
53
Ischemic stroke is an acute cerebrovascular condition in which blood flow to a brain region is suddenly interrupted, leading to tissue infarction. Neurons depend on continuous oxygen and glucose supply, so even brief reductions in perfusion cause energy failure, ionic imbalance, and irreversible injury. Ischemic strokes are classified into thrombotic and embolic types based on their underlying mechanisms.Thrombotic MechanismsThrombotic stroke develops when a clot forms within a cerebral artery.
53
01:15Ischemic Stroke ll: Pathophysiology
68
An ischemic stroke occurs when a cerebral blood vessel becomes obstructed, most often by a thrombus or embolus, interrupting the delivery of oxygen and glucose to brain tissue. Because neurons rely on continuous aerobic metabolism, energy failure begins within minutes of reduced perfusion. The region receiving the least blood flow becomes the infarct core, an area of irreversible cellular death. Surrounding this core lies the penumbra, a zone of hypoperfused but still viable tissue that is...
68
01:17Hemorrhagic Stroke l: Introduction
34
A hemorrhagic stroke is an acute neurological event that occurs when a weakened cerebral blood vessel ruptures, allowing blood to accumulate within or around the brain. The sudden release of blood forms a focal hematoma that increases intracranial pressure, displaces neural tissue, and can obstruct cerebrospinal fluid pathways. These effects may be compounded by intraventricular extension of the hemorrhage, cerebral edema, or compression of adjacent structures, all of which contribute to...
34
01:29Hemorrhagic Stroke ll: Pathophysiology
52
A hemorrhagic stroke develops when a cerebral blood vessel ruptures, allowing blood to escape into the surrounding brain tissue, as in intracerebral hemorrhage (ICH), or into the subarachnoid space, as in subarachnoid hemorrhage (SAH). Because the skull is a rigid compartment, the sudden presence of extravascular blood rapidly increases intracranial pressure and compresses adjacent neural structures, leading to immediate tissue injury and impaired cerebral perfusion.Mass Effect and Primary...
52
01:26Transient Ischemic Attack l: Introduction
34
A transient ischemic attack (TIA) is a brief episode of neurological dysfunction caused by a temporary, focal reduction in cerebral blood flow. Although symptoms resemble those of an ischemic stroke, the interruption in perfusion is short-lived and does not cause permanent infarction. TIAs are clinically important because they often serve as early warning events for future stroke.Mechanisms of Transient Cerebral IschemiaTransient cerebral ischemia may arise through several mechanisms. One...
34