Unmasking COVID-19: Unveiling the Virus’s Impact on the Brain
Delving Deeper into the Enigma of COVID-19’s Neurological Implications
In the early days of the COVID-19 pandemic, medical professionals began to identify a startling pattern.
Though primarily recognized as a respiratory virus, SARS-CoV-2 had a profound impact on the brain, leading to a range of symptoms from anosmia and dysgeusia (loss of taste and smell) to ‘brain fog’ and, in severe cases, stroke.
In response, New York City’s NYU Langone Health launched a research initiative to unravel the mysteries of the virus’s effects on the brain and nervous system.
Over time, this initiative expanded beyond acute symptoms, pivoting towards long-term neurological complications experienced by individuals suffering from Long COVID, as per program director Dr. Sharon Meropol.
Traversing the Pandemic’s Neurological Terrain
Meropol’s team, along with other researchers, embarked on a journey to investigate a multitude of neurocognitive complications.
Their findings revealed a troubling link between SARS-CoV-2 infections and cognitive decline, alterations in brain size and structure, depression, suicidal ideation, tremors, seizures, memory loss, and new onset or worsened dementia.
These long-term difficulties could arise even in patients with relatively mild COVID-19 symptoms.
The real conundrum, according to Meropol, lies in decoding the processes occurring within the brains of COVID-19 patients and finding ways to reverse the damage.
Navigating Gray Areas
Upon examining the brain of someone infected with certain viruses like rabies, it’s clear that the brain is infected, states Dr. Avindra Nath, clinical director of the National Institute of Neurological Disorders and Stroke (NINDS). However, SARS-CoV-2 presents a more ambiguous picture.
Early in the pandemic, Nath and his colleagues scanned and analyzed the brains of 13 COVID-19 fatalities. While the SARS-CoV-2 virus was not detected in these brains, they found significant damage to the blood vessels, which were shrouded in antibodies.
This suggested an immune response gone awry, leading to widespread inflammation in the brain, potentially causing catastrophic damage, even to areas controlling breathing.
In COVID-19 survivors, brain inflammation could also be responsible for long-term symptoms like brain fog and memory loss, though Nath emphasizes that this is not yet certain.
Inflammation: The Common Thread
Dr. Lara Jehi, a researcher at the Cleveland Clinic, highlights inflammation as a potential instigator of COVID-19’s neurological symptoms.
Her research found evidence of abnormal inflammation in individuals with chronic post-COVID headaches.
Moreover, a 2021 study by Jehi and her colleagues observed numerous similarities between Long COVID and Alzheimer’s disease, specifically concerning brain inflammation and microscopic blood vessel damage.
Direct Assault or an Immune Overreaction?
Despite Nath’s findings, subsequent research identified the virus in the brains of COVID-19 victims. A 2022 study in Nature found SARS-CoV-2 genetic material in the central nervous system tissue of 11 out of 12 subjects, confirming the virus’s ability to infiltrate and replicate within the human brain.
Yet, inconsistencies in research findings highlight the need for continued investigation into whether SARS-CoV-2 directly affects the brain or triggers an immune response leading to neurological changes.
Potential Treatment Pathways for Long COVID
While a ‘one-size-fits-all’ solution is unlikely, the search for treatments continues. Dr. Wes Ely from Vanderbilt University Medical Center believes that cognitive rehabilitation through targeted mental exercises could aid those with similar cognitive declines following intensive care unit stays.
Meanwhile, NINDS is exploring immunotherapy for neurological Long COVID, using therapies already in use for a range of autoimmune and neurological conditions. Preliminary research also indicates that blood-thinning drugs could help alleviate Long COVID symptoms by breaking up micro clots linked to systemic inflammation.
Currently, there are no proven therapies for Long COVID symptoms, but Ely remains optimistic about the potential for brain recovery. He states, “The brain is incredibly neuroplastic, and it can do amazing things.”
Following Nath’s initial investigation, other researchers indeed detected the virus within the brains of COVID-19 fatalities.
A compelling 2022 study in Nature thoroughly analyzed the brain tissue of 11 people who were infected with COVID-19 at the time of their death.
Remarkably, all but one of these individuals demonstrated the presence of the virus’s genetic material within their central nervous system tissue, conclusively demonstrating that SARS-CoV-2 is indeed capable of invading and replicating within the human brain.
However, Nath still views this as an open question requiring further research. Despite the ongoing study of COVID-19 patient brains, his team has yet to find indisputable evidence of the SARS-CoV-2 virus within these organs.
In a single instance, they discovered viral proteins – but not the complete virus – within biopsied
Similarly, a preliminary study from April 2023 also found SARS-CoV-2 spike proteins within the brains of individuals who died from COVID-19. These proteins allow the virus to enter human cells.
An Unresolved Mystery: SARS-CoV-2 and the Brain
Despite these findings, Nath describes the research as “inconsistent”. Some studies have identified the virus within the brain, while others have not. Even when found, the amounts of the virus are often minute, leaving a significant knowledge gap.
Dr. Wes Ely, a brain disease researcher at Vanderbilt University Medical Center, is convinced that SARS-CoV-2 can damage the “support cells” of the brain. These cells play a critical role in maintaining brain and body function. Damage to these cells can trigger a domino effect leading to tissue death within the brain.
The Multifaceted Assault of COVID-19 on the Brain
However, Ely concedes, “Almost certainly there are multiple processes going on.” It’s plausible that the virus both directly affects the brain and initiates changes in the immune system that result in neurocognitive complications. He emphasizes, “We’re not looking for a magic bullet that will solve all these problems at once.”
In the absence of a single solution, that doesn’t mean no solution exists. Ely has observed that “cognitive rehab”, a process of rebuilding the brain’s function through targeted mental exercises, can benefit individuals who develop similar cognitive decline following stays in the intensive-care unit.
Potential Solutions on the Horizon
Despite its potential risks for Long COVID patients who often experience worsened symptoms after mental or physical exertion, Ely proposes modulating the immune system’s function to reduce inflammation in the brains of Long COVID patients as a promising approach.
NINDS is currently recruiting patients for a study on immunotherapy as a potential treatment for neurological Long COVID.
This approach is particularly exciting, Nath explains because it utilizes therapy already in use to treat a range of autoimmune and neurological conditions. If proven effective, this could rapidly benefit Long COVID patients.
In addition to these promising therapies, preliminary research also suggests that blood-thinning drugs may assist in breaking up tiny “micro clots” in the blood linked to systemic inflammation, potentially relieving Long COVID symptoms, including fatigue, brain fog, and difficulty concentrating.
As it stands, there are no proven therapies for people with Long COVID symptoms, whether neurological or otherwise.
Yet, Ely remains optimistic that COVID-related brain changes are reversible, reinforcing his faith in the brain’s neuroplasticity, its incredible capacity to adapt and recover. “The brain is incredibly neuroplastic,” he reiterates, “and it can do amazing things.”
Source: Scientists Are Just Beginning to Understand COVID-19’s Effect On the Brain
