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Impact of COVID-19 Vaccines on Cerebrovascular Health

NCT04992195 · Status: RECRUITING · Type: OBSERVATIONAL · Enrollment: 500

Last updated 2026-02-24

No results posted yet for this study

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

Interventions

DIAGNOSTIC_TEST

Laboratory tests and Montreal Cognitive Assessment

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.

DIAGNOSTIC_TEST

Laboratory tests and Montreal Cognitive Assessment

Laboratory tests at baseline and serological testing for IgG antibody to exclude past COVID-19 infection. The timing of the second MRI brain, laboratory tests, clinical and cognitive assessment will be matched with the timing in the vaccination group are available.

Sponsors & Collaborators

  • Chinese University of Hong Kong

    lead OTHER

Principal Investigators

  • Bonaventure Yiu Ming IP, MB ChB · Chinese University of Hong Kong

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2021-07-05
Primary Completion
2026-06-30
Completion
2026-12-31

Countries

  • Hong Kong

Study Locations

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Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT04992195 on ClinicalTrials.gov