Study Links Long Covid Symptoms to Alzheimer’s Disease Mechanisms

A recent study has put forward evidence that long Covid, characterised by enduring symptoms following a SARS-CoV-2 infection, may share underlying mechanisms with Alzheimer’s disease. Researchers from New York University revealed that individuals experiencing long Covid reported a significant enlargement of the choroid plexus (ChP), a network of blood vessels responsible for producing cerebrospinal fluid that protects the brain. The ChP plays a crucial role in regulating immune responses, particularly in managing inflammation and clearing waste from the brain.

Investigations have indicated that disruptions to the brain's waste clearance processes can contribute to dementia, with Alzheimer’s disease being the most prevalent form. The research team highlighted that the COVID-19 virus has been associated with damage to the cells lining the blood vessels making up the choroid plexus.

In the study, the authors noted, “Long coronavirus disease (COVID) patients show choroid plexus enlargement and reduced cerebral blood flow. ChP alterations are associated with Alzheimer’s disease-related symptoms and plasma biomarker changes.” Their findings also emphasised that the increase in choroid plexus size correlates with elevated levels of specific blood proteins, such as ‘pTau217’, which have been previously linked to the progression of Alzheimer’s disease.

Additionally, the researchers identified the presence of blood proteins like glial fibrillary acidic protein, known to rise following brain injury. Participants with a larger choroid plexus demonstrated an average decline of two per cent on the Mini-Mental State Examination, a widely used 30-point screening tool for cognitive changes and memory loss.

Yulin Ge, senior author of the study and a professor in the department of radiology at New York University’s School of Medicine, stated, “Our work suggests that long-term immune reactions caused in some cases after an initial COVID infection may come with swelling that damages a critical brain barrier in the choroid plexus.” Ge further indicated that this enlargement could act as an early indicator of potential cognitive decline similar to that seen in Alzheimer’s patients.

Symptoms associated with long Covid frequently include cognitive challenges such as memory issues and difficulty concentrating. The study involved 179 participants comprising 86 individuals exhibiting neurological symptoms of long Covid, 67 who had fully recovered without lingering effects, and 26 who had never contracted COVID-19. Each participant underwent magnetic resonance imaging (MRI) scans to assess their brain structures.

The results revealed not just an increase in the overall volume of the choroid plexus among those with long Covid but also a decrease in blood flow through its vessels. While the specific mechanisms remain to be conclusively identified, the research team proposed that these observations might reflect inflammation-related vascular changes in the choroid plexus. Such changes result from long-term immune system activation, leading to thickened layers in the blood vessel lining and associated scarring, which negatively impacts blood flow.

The authors noted that reduced blood perfusion in the choroid plexus might hinder the production of cerebrospinal fluid, subsequently causing waste accumulation and compromising the integrity of the blood-cerebrospinal fluid barrier.

Moving forward, Thomas Wisniewski, another senior author and a professor in the department of neurology at New York University’s School of Medicine, stated, “Our next step is to follow these patients over time to see if the brain changes we identified can predict who will develop long-term cognitive issues.” Wisniewski emphasised that larger studies will be necessary to determine whether these alterations in the choroid plexus are a cause or consequence of neurological symptoms, which could inform future treatment strategies.

In a related finding, a previous study published in the European Heart Journal in August 2025 reported that COVID-19 infections may lead to an accelerated aging of blood vessels by up to five years, with women disproportionately affected compared to men.