Examining the effects of COVID-19 vaccines on brain health

Impact of COVID-19 Vaccines on Cerebrovascular Health - a Population-based Study

Observational Chinese University of Hong Kong · NCT04992195

This study is trying to see how COVID-19 vaccines affect brain health by comparing brain scans of vaccinated people to those who haven't been vaccinated.

Quick facts

Study typeObservational
Enrollment500 (estimated)
Ages18 Years and up
SexAll
SponsorChinese University of Hong Kong Academic / other
Locations1 site (Hong Kong)
Trial IDNCT04992195 on ClinicalTrials.gov

What this trial studies

This observational study aims to assess the impact of COVID-19 vaccinations on cerebrovascular health among citizens from the CUHK Brain Health Longitudinal Study cohort in Hong Kong. Participants who have received either the SinoVac or BioNTech vaccine will undergo a second MRI brain scan approximately 16 weeks after their second dose, while a control group of unvaccinated individuals will also be evaluated. The study will collect demographic data, medical histories, and laboratory tests to analyze any changes in cerebrovascular conditions post-vaccination. The goal is to address concerns regarding vaccination-related cerebrovascular accidents and enhance understanding of vaccine safety.

Who should consider this trial

Good fit: Ideal candidates include citizens from the CUHK Brain Health Longitudinal Study cohort who have received COVID-19 vaccinations and have undergone baseline MRI assessments.

Not a fit: Patients with pre-existing neurological conditions such as stroke or dementia, or those unable to provide informed consent, will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide valuable insights into the safety of COVID-19 vaccines concerning cerebrovascular health, potentially alleviating vaccine hesitancy.

How similar studies have performed: While there have been studies examining vaccine safety, this specific focus on cerebrovascular health post-COVID-19 vaccination is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

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

Exclusion Criteria:

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

Where this trial is running

Hong Kong

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions StrokeStroke, AcuteStroke, IschemicDementiaBrain IschemiaAlzheimer DiseaseBrain DiseasesMajor Adverse Cardiovascular Event
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.