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.
None
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.
1\. Chinese ONLY 2. Hong Kong Resident
Case-control
Prospective
Laboratory tests and Montreal Cognitive Assessment
Diagnostic testLaboratory 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.
Laboratory tests and Montreal Cognitive Assessment
Diagnostic testLaboratory 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.
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.
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.
Click on the lead sponsor to view all of their trials.
