Post by Nadica (She/Her) on Sept 14, 2024 23:31:53 GMT
What We Know About Covid’s Impact on Your Brain - Published Sept 13, 2024
By Jason Gale
Scientists are worried that persisting cognitive issues may signal a coming surge of dementia and other mental conditions
Many of Covid’s earliest and most alarming effects involve the brain, including a lost sense of smell, sluggish thinking, headaches, delirium and strokes. More than four years after the pandemic began, researchers are recognizing the profound impacts Covid can have on brain health, as millions of survivors suffer from persistent issues such as brain fog, depression and cognitive slowing, all of which hinder their ability to work and otherwise function. Scientists now worry that these symptoms may be early indicators of a coming surge in dementia and other mental conditions, prolonging the pandemic’s societal, economic and health burden.
What Studies Show
In 2021, UK researchers reported early results from a study comparing brain scans taken before and after the pandemic began. They discovered signs of damage and accelerated aging in the brain, particularly in the region responsible for smell, even in patients who had experienced mostly mild cases of Covid months earlier.
How Does Covid-19 Impact the Brain?
Research has since shown that Covid-related cognitive deficits can persist for years, especially in older adults and those who suffered more severe cases. For instance, a study of seniors hospitalized during China’s first Covid wave showed that 2 1/2 years later, 40% developed cognitive impairment, compared with just 14% of their uninfected spouses. A 2024 UK study of people hospitalized for Covid treatment revealed a significant worsening of psychiatric and cognitive symptoms three years after discharge. Half experienced moderate to severe depression, a quarter suffered severe cognitive decline, and one in nine showed a loss of mental function equivalent to a 30-point drop on the IQ scale, where a score of 100 is average.
For patients already battling Alzheimer’s disease, Covid can exacerbate brain inflammation, damage immune cells, and accelerate the memory-robbing disease itself, studies indicate. Even previously healthy older adults face an increased risk of cognitive impairment and new-onset dementia after infection. Mild Covid cases in younger adults have also been linked to brain issues affecting memory and thinking. These symptoms may be permanent but typically fluctuate and tend to worsen after physical or mental exertion, often impairing the ability of individuals to work and socialize.
Younger Americans Report More Cognitive Disability
A February study of nearly 113,000 people found greater deficits in memory and executive function among people who had been infected at some point compared with those who had never had the SARS-CoV-2 virus. Those struck later in the pandemic had smaller deficits compared with those infected with the original strain or the alpha variant, the first new version of the virus to come to researchers’ attention. The study also noted a slight cognitive benefit for people who received two or more vaccinations.
Even mild cases of Covid led to cognitive decline, equivalent to an average 3-point drop in IQ. For those with unresolved symptoms such as persistent shortness of breath or fatigue, the decline amounted to a 6-point decrease in IQ.
Some evidence suggests the infection may increase the risk of Parkinson’s disease. This link is supported by the rise in cases of parkinsonism — a collection of symptoms such as tremors, slow movement, stiffness and balance issues — following Covid.
How Covid Harms the Brain
The effects of a SARS-CoV-2 infection on the brain are the focus of intense research and remain only partially understood. Studies suggest that during acute infection, the virus may damage nerves, particularly in the olfactory bulb — which houses the nerves that transmit smell impulses to the brain — leading to problems that can persist for years. In some cases, the virus may infect the brain through this pathway, altering the organ’s structure and resulting in impaired cognition and fatigue.
Persistent viral remnants or the initial infection itself may trigger neuroinflammation and disrupt the immune system, causing antibodies and T cells to mistakenly attack healthy brain cells, damage blood vessels, and harm the blood-brain barrier. Additional research points to blood clots that may drive immune activation, restricting the supply of oxygen and nutrients to the brain, and altered levels of key hormones cortisol and dopamine that may be linked to changes in gut health.
Possible Economic Impact
While the long-term effects of Covid on conditions such as Parkinson’s disease and dementia remain uncertain, the stakes are high. These are both lifelong, incurable, progressive illnesses with a profound societal impact, affecting not only those diagnosed but also their families, caregivers, and the broader healthcare system.
Already, there are significant economic repercussions globally from the enduring prevalence of long Covid, a loosely defined umbrella term to describe new, returning or ongoing health problems of varying severity that occur after a case of SARS-CoV-2 infection. By the end of 2023, long Covid had affected an estimated 400 million people worldwide. Analysts have put the annual economic toll at between $864 billion to $1.04 trillion in developed nations alone – roughly 1% of the global economy. Much of the impact arises from the ongoing disability and illness experienced by sufferers, with persistent fatigue and concentration problems among the most common.
By Jason Gale
Scientists are worried that persisting cognitive issues may signal a coming surge of dementia and other mental conditions
Many of Covid’s earliest and most alarming effects involve the brain, including a lost sense of smell, sluggish thinking, headaches, delirium and strokes. More than four years after the pandemic began, researchers are recognizing the profound impacts Covid can have on brain health, as millions of survivors suffer from persistent issues such as brain fog, depression and cognitive slowing, all of which hinder their ability to work and otherwise function. Scientists now worry that these symptoms may be early indicators of a coming surge in dementia and other mental conditions, prolonging the pandemic’s societal, economic and health burden.
What Studies Show
In 2021, UK researchers reported early results from a study comparing brain scans taken before and after the pandemic began. They discovered signs of damage and accelerated aging in the brain, particularly in the region responsible for smell, even in patients who had experienced mostly mild cases of Covid months earlier.
How Does Covid-19 Impact the Brain?
Research has since shown that Covid-related cognitive deficits can persist for years, especially in older adults and those who suffered more severe cases. For instance, a study of seniors hospitalized during China’s first Covid wave showed that 2 1/2 years later, 40% developed cognitive impairment, compared with just 14% of their uninfected spouses. A 2024 UK study of people hospitalized for Covid treatment revealed a significant worsening of psychiatric and cognitive symptoms three years after discharge. Half experienced moderate to severe depression, a quarter suffered severe cognitive decline, and one in nine showed a loss of mental function equivalent to a 30-point drop on the IQ scale, where a score of 100 is average.
For patients already battling Alzheimer’s disease, Covid can exacerbate brain inflammation, damage immune cells, and accelerate the memory-robbing disease itself, studies indicate. Even previously healthy older adults face an increased risk of cognitive impairment and new-onset dementia after infection. Mild Covid cases in younger adults have also been linked to brain issues affecting memory and thinking. These symptoms may be permanent but typically fluctuate and tend to worsen after physical or mental exertion, often impairing the ability of individuals to work and socialize.
Younger Americans Report More Cognitive Disability
A February study of nearly 113,000 people found greater deficits in memory and executive function among people who had been infected at some point compared with those who had never had the SARS-CoV-2 virus. Those struck later in the pandemic had smaller deficits compared with those infected with the original strain or the alpha variant, the first new version of the virus to come to researchers’ attention. The study also noted a slight cognitive benefit for people who received two or more vaccinations.
Even mild cases of Covid led to cognitive decline, equivalent to an average 3-point drop in IQ. For those with unresolved symptoms such as persistent shortness of breath or fatigue, the decline amounted to a 6-point decrease in IQ.
Some evidence suggests the infection may increase the risk of Parkinson’s disease. This link is supported by the rise in cases of parkinsonism — a collection of symptoms such as tremors, slow movement, stiffness and balance issues — following Covid.
How Covid Harms the Brain
The effects of a SARS-CoV-2 infection on the brain are the focus of intense research and remain only partially understood. Studies suggest that during acute infection, the virus may damage nerves, particularly in the olfactory bulb — which houses the nerves that transmit smell impulses to the brain — leading to problems that can persist for years. In some cases, the virus may infect the brain through this pathway, altering the organ’s structure and resulting in impaired cognition and fatigue.
Persistent viral remnants or the initial infection itself may trigger neuroinflammation and disrupt the immune system, causing antibodies and T cells to mistakenly attack healthy brain cells, damage blood vessels, and harm the blood-brain barrier. Additional research points to blood clots that may drive immune activation, restricting the supply of oxygen and nutrients to the brain, and altered levels of key hormones cortisol and dopamine that may be linked to changes in gut health.
Possible Economic Impact
While the long-term effects of Covid on conditions such as Parkinson’s disease and dementia remain uncertain, the stakes are high. These are both lifelong, incurable, progressive illnesses with a profound societal impact, affecting not only those diagnosed but also their families, caregivers, and the broader healthcare system.
Already, there are significant economic repercussions globally from the enduring prevalence of long Covid, a loosely defined umbrella term to describe new, returning or ongoing health problems of varying severity that occur after a case of SARS-CoV-2 infection. By the end of 2023, long Covid had affected an estimated 400 million people worldwide. Analysts have put the annual economic toll at between $864 billion to $1.04 trillion in developed nations alone – roughly 1% of the global economy. Much of the impact arises from the ongoing disability and illness experienced by sufferers, with persistent fatigue and concentration problems among the most common.