We shall recruit all consecutive citizens from a prospective, population-based cohort
from the CUHK Brain Health Longitudinal Study free of clinically evident neurological
diseases. The CUHK Brain Health Longitudinal Study cohort comprises of an
epidemiologically representative sample from all socio-economic classes in the 18
districts of Hong Kong with reference to government census data. All citizens received
baseline cognitive assessment and evaluation of metabolic risk factors. Baseline micro-
and macro-cerebrovascular abnormalities were evaluated by MRI brain on recruitment.
We shall phone contact the citizens who met the inclusion criteria to enquire their
vaccination plan. Citizens who received COVID-19 vaccination (SinoVac or BioNTech) and
willing to join the study, our services coordinator, co-investigator or principal
investigator will interview and explain the study in details and obtain the participant's
consent. After signing the consent, the participant shall undergo a 2nd MRI brain 16
weeks (+/-4 weeks) after the 2nd dose of vaccination. The control group is defined as
citizens who have not received any COVID-19 vaccines nor clinically/serologically evident
SARS-CoV-2 infection.
We shall collect the following information for the vaccination group:
Demographic data ; Medical co-morbidities ; Laboratory tests at baseline and 16 weeks
(+/-4 weeks) after 2nd dose of vaccine and serological testing for IgG antibody. We shall
conduct a face-to-face assessment 16 weeks (+/-4 weeks) 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.
On the other hand, we shall collect the following information for the control group:
Demographic data ; Medical co-morbidities ; Laboratory tests at baseline and serological
testing for Immunoglobulin G (IgG) antibody to exclude past COVID-19 infection prior to
the second MRI brain.The timing of the second MRI brain, laboratory tests, clinical and
cognitive assessment in the control group will be matched with the timing in the
vaccination group are available.
The proposed study does not involve formulating new diagnoses or directly offering
treatment for neurological and/or psychiatric conditions. All patients admitted to PWH or
other medical institutes will be treated according to the standard care at the
corresponding institution, regardless of their decision to participate in this
repository. Should results from this study lead to discovery of one or more factors
associated with development of brain disease, the principal investigators,
co-investigators, or study coordinator will inform, counsel and offer diagnostic and/or
therapeutic recommendations to participants accordingly. The participants may be referred
to relevant departments for follow-up clinical visits.
Safe and effective 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. However, 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. The proposed study will allow us to address
the apprehension of cerebrovascular accidents after vaccination is the provision of
evidence-based information of the impact of COVID-19 vaccines on brain health.