On 5 January, in a Perspective article published in Alzheimers & Dementia, the US Alzheimer's Association announced the launch of a global study to evaluate the long-term neurological consequences of COVID-19. The CNS SARS-CoV-2 study will be led by a global consortium from 30 different countries, receiving technical advice from the World Health Organisation (WHO), and focusing on the link between the coronavirus and cognitive decline, Alzheimer's Disease (AD) and dementia.
In the article, lead author Prof. Gabriel de Erausquin and colleagues outline what we currently know about SARS-CoV-2 - the coronavirus that causes COVID-19 - and the central nervous system (CNS). Describing evidence which suggests that coronaviruses can directly infect brain cells, they outline how SARS-CoV-2 may enter endothelial cells (specialised cells that line the inside of our blood vessels) by binding to ACE2 receptors, kicking off an inflammatory cascade that culminates in vascular dysfunction and disease. COVID-19 infection in older people is associated with several neurological symptoms, including delirium, loss of taste, altered behaviour and cognition. However, it is not yet known whether these symptoms are due to direct effects of COVID-19 on the brain - or indirect, systemic effects on other body systems. In particular, the authors highlight the established link between vascular disease and cognitive decline, suggesting that the increased incidence of stroke and vascular problems after COVID-19 infection may also contribute to an elevated long-term risk of dementia in recovered individuals.
To better understand the long-term consequences of SARS-CoV-2 on the brain, cognition and dementia, the CNS SARS-CoV-2 study will link study teams from many different countries worldwide, which together have reported over 22 million cases of COVID-19. With participants already enrolled in dementia research studies, the CNS SARS-CoV-2 consortium will study how people with or without COVID-19 progress following diagnosis, aiming to enrol around 40,000 COVID-19 survivors in total. Specific measures to be evaluated include cognition, behaviour and, where possible, brain volume - as measured using MRI scans. The study will initially be funded by the Alzheimer's Association, with researchers also seeking funding from their respective countries.
