Impact of COVID-19 Vaccines on Cerebrovascular Health

NCT04992195 | Recruiting

• 1 other identifier: CREC No. 2021.386
• Study Type: observational
• Target: 500
• Locations: 1 country
• Sites: 1

Brief Summary

Safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may reduce the transmission of and achieve population immunity against the COVID-19 pandemic, which accounted for more than 3.75million deaths worldwide. With World Health Organization's (WHO) effort on ensuring equitable access to COVID-19 vaccines, vaccination rate may increase in the near future. On the other hand, vaccination hesitancy has emerged as a major hindrance on the global vaccination campaigns in certain areas due to safety concerns, social factors, and public health policies. For instance, a recent survey conducted in Hong Kong showed a low vaccine acceptance rate of 37%. Long-term safety concerns and post-vaccination events relayed by the social media maybe reasons for vaccination hesitancy. Among which, cerebrovascular accidents (CVA) after vaccination were one of the most frequently reported post-vaccination events. These reports ranged from ischemic strokes in elderly patients with multiple cardiovascular co-morbidities, to hemorrhage strokes in otherwise "young-and-fit" adults. While many of these events were investigated by the COVID-19 immunization expert committee, an important premise to address the apprehension of CVA after vaccination is the provision of evidence-based information of the impact of COVID-19 vaccines on brain health. In this prospective, longitudinal, observational study, we aim to elucidate the relationship between COVID-19 vaccines and cerebrovascular health in healthy citizens in a population-based cohort.

Conditions

Stroke; Stroke, Acute; Stroke, Ischemic; Dementia; Brain Ischemia; Alzheimer Disease; Brain Diseases; Major Adverse Cardiovascular Event; Arterial Thromboembolism; Venous Thromboembolism

Outcome Measures

Primary Outcomes (2)

• Imaging markers

  We shall perform cranial MRI examinations in a 3-Tesla scanner (MAGNETOM Prisma; Siemens AG, Munich, Germany). The scanning protocol will employ a standard stroke protocol MRI scan with axial T1-weighted, T2-weighted, FLAIR, susceptibility weighted imaging, diffusion weighted imaging, and time-of-flight magnetic resonance angiography (MRA) sequences.

  December, 2026

• Imaging analysis

  Blinded to the time sequence, clinical outcomes and the vaccination status, an experienced neuro-radiologist and an experienced stroke neurologist shall independently evaluate the imaging markers (as stated in endpoint assessment above). Disparity will be resolved by discussion. White matter hyperintensity volume will be gauged by FMRIB's Software Library Brain Intensity Abnormality Classification Algorithm (BIANCA), a fully automated, supervised method for white matter hyperintensities detection. Brain volume will be measured by FMRIB's Software Library voxel-based morphometry analysis.Siemens AG, Munich, Germany). The scanning protocol will employ a standard stroke protocol MRI scan with axial T1-weighted, T2-weighted, FLAIR, susceptibility weighted imaging, diffusion weighted imaging, and time-of-flight magnetic resonance angiography (MRA) sequences.

  December, 2026

Study Arms (2)

Vaccination Group

Citizens who received baseline cognitive assessment and evaluation of metabolic risk factors from the CUHK Brain Health Longitudinal Study. Baseline micro- and macro-cerebrovascular abnormalities were evaluated by MRI brain on recruitment and received COVID-19 vaccination (SinoVac or BioNTech).

Diagnostic Test: Laboratory tests and Montreal Cognitive Assessment

Control Group

Citizens who received baseline cognitive assessment and evaluation of metabolic risk factors from the CUHK Brain Health Longitudinal Study. Baseline micro- and macro-cerebrovascular abnormalities were evaluated by MRI brain on recruitment and have not received any COVID-19 vaccines nor clinically/serologically evident SARS-CoV-2 infection.

Diagnostic Test: Laboratory tests and Montreal Cognitive Assessment

Interventions

Laboratory tests and Montreal Cognitive Assessment DIAGNOSTIC_TEST

Laboratory tests at baseline and 16 weeks (+/-4 weeks) after 2nd dose of vaccine and serological testing for IgG antibody. Participants who have a scheduled vaccination date shall undergo an MRI brain 16 weeks (+/-4 weeks) after the second dose of COVID-19 vaccination (either SinoVac or BioNTech). A face-to-face assessment 16 weeks (+/-4 weeks) will also be conducted after the 2nd dose of COVID-vaccine for evaluation of any clinical events, followed by a phone visit every 6 months. Cognitive assessment by MoCA will be performed at baseline, 16 weeks (+/-4 weeks) then every 12 months after the 2nd dose of COVID-19 vaccine.

Vaccination Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

1\. Chinese ONLY 2. Hong Kong Resident

You may qualify if:

• All consecutive citizens in the CUHK Brain Health Longitudinal Study cohort who received baseline MRI brain.

You may not qualify if:

• Citizens with clinically evident stroke or dementia prior to recruitment; or
• Citizens who are unable to provide an informed consent; or
• Citizen with contraindications to MRI brain, e.g., non-MRI compatible implants, claustrophobia, etc; or
• Citizens who had no baseline MRI brain assessment.

Sponsors & Collaborators

• Chinese University of Hong Kong: lead

Study Sites (1)

Chinese University of Hong Kong

Hong Kong, Hong Kong

RECRUITING

MeSH Terms

Conditions

Stroke; Ischemic Stroke; Dementia; Brain Ischemia; Alzheimer Disease; Brain Diseases; Venous Thromboembolism

Condition Hierarchy (Ancestors)

Cerebrovascular Disorders; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Neurocognitive Disorders; Mental Disorders; Tauopathies; Neurodegenerative Diseases; Thromboembolism; Embolism and Thrombosis

Study Officials

• Bonaventure Yiu Ming IP, MB ChB

  Chinese University of Hong Kong

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Bonaventure Yiu Ming IP, MB ChB

CONTACT

852-28902002; bonaventureip@cuhk.edu.hk

Thomas Wai Hong LEUNG, MB ChB

CONTACT

852-28902002; drtleung@cuhk.edu.hk

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Clinical Lecturer

Study Record Dates

• First Submitted: August 3, 2021
• First Posted: August 5, 2021
• Study Start: July 5, 2021
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: February 24, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

HK (1)