This is a cross-sectional study composed of three participant groups. 1) persons previously infected with COVID-19 experiencing CNS-PASC (central nervous system Post-Acute Sequelae of COVID-19) within 6 months of recovery, 2) persons previously infected with COVID-19 without CNS-PASC symptoms within 6 months of recovery, and 3) a control group of persons not previously infected with COVID-19. Groups will be as similar as possible for age and substance use. This study will examine synaptic vesicular density (henceforth, synaptic density), as measured with positron emission tomography (PET), and neuroinflammation markers, as measured with Magnetic resonance imaging (MRI), as well as clinical, cognitive, and peripheral biomarkers between the groups.~Participants that meet the inclusion and exclusion criteria at the initial screening visit (Visit 1) and provide written consent will be enrolled into the study. Participants will undergo PET scans with the novel PET tracer [18F]SDM-8 to quantify synaptic density levels. MRI scans will be collected, and clinical assessments will be completed at the same time. Each participant will participate in four study visits at defined time points over the course of their enrolment, including the initial participant screening visit (Visit 1). Brain imaging scans and PASC/cognitive assessments will occur at visits 2 and 3, followed by a subsequent PASC/cognitive assessment follow-up at visit 4, occurring 2-3 months after Visit 3.
Over one million Canadians have been infected by COVID-19. Many people who have been infected by COVID-19 experience negative mental symptoms, such as brain fog and fatigue. For many of these people, they continue to feel these negative mental symptoms even after recovering from COVID-19. However, scientists still do not know how COVID-19 harms the human brain and causes these mental problems. Our goal is to use advanced brain imaging to determine whether people who have been infected with COVID-19 show damage in their brain. We hope that this information will help doctors determine what treatments should be provided to help people who are suffering from continuing mental problems after being infected with COVID-19.