- Having COVID-19 has been linked to an increased risk of neurological issues.
- Researchers say COVID has contributed to more than 40 million new cases of neurological disorders worldwide.
- Though scientists don't yet know how or why COVID impacts brain health, preventing the illness is still key to maintaining long-term health.
Scientists are just starting to uncover all of the ways in which COVID affects the brain and central nervous system, but growing evidence has shown that the infection can trigger a variety of neurological issues.
New research published in Nature Medicine found that brain and neurological disorders—including stroke, migraine, and depression and anxiety—occurred 7% more often in people who had COVID-19, compared to those who were never infected.
“COVID can lead to long-term neurologic consequences in some people,” study co-author Ziyad Al-Aly, MD, a clinical epidemiologist at Washington University in Saint Louis and the chief of research at the VA Saint Louis Health Care System, told Health. “It is not only brain fog—the neurologic complications include strokes, migraines, epilepsy and seizures, inflammation of the brain, and several other disorders.”
Overall, researchers said COVID has contributed to more than 40 million new cases of neurological disorders worldwide.
“We’re seeing brain problems in previously healthy individuals and those who have had mild infections,” Dr. Al-Aly said in a press release. “It doesn’t matter if you are young or old, female or male, or what your race is. It doesn’t matter if you smoked or not, or if you had other unhealthy habits or conditions.”
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COVID Infection Heightens Risk of Neurological Disorders
As part of the new study, researchers evaluated the health records of 154,068 veterans who tested positive for COVID between March 1, 2020 to January 15, 2021, and identified those who developed neurologic disorders within 12 months of being infected.
Researchers compared that data to the medical records of 5.6 million people who didn’t have COVID during that same timeframe and another 5.8 million people whose health data was collected before the pandemic.
Compared with the control groups, those who were infected with COVID had a 77% higher risk of memory problems within a year after being infected. They were also 50% more likely to have an ischemic stroke, 80% more likely to have seizures, 43% more likely to have mental health issues, 35% more likely to have headaches and 42% more likely to develop movement disorders like tremors.
Prior research on COVID’s impact on brain health has largely focused on hospitalized patients. This study found that the risk of brain injury increased with the level of care the patient received and is one of the first reports to show that even people who had COVID but were not hospitalized faced a greater risk of developing neurological complications down the road.
In extrapolating that data, researchers postulated that roughly 6.6 million people in the U.S. have likely suffered brain impairments due to the virus.
This risk of neurologic disease could have massive impacts on quality of life and lifespan, as well as our healthcare system and economy. The researchers said they hope their findings will inform policies that’ll address the ongoing neurological problems people with COVID may experience in the months and years ahead.
While Dr. Al-Aly said he was expecting to see that COVID was associated with higher rates of cognitive impairment and stroke—as that has been well demonstrated in previous literature—he was surprised by the degree of the problems.
“What was most remarkable though is when you put everything together and you see the extent of the problems that could be caused by COVID—that was the eye opener. It is not only just brain fog or strokes, it is much more extensive than that,” said Dr. Al-Aly.
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How COVID Impacts Brain Health
Though many research groups are actively working to identify the mechanisms behind the neurological issues, scientists don’t yet have a solid understanding of why and how COVID impacts brain health. There are, however, a few common theories that may explain how the virus interacts with our brain.
It’s well known that COVID can trigger widespread inflammation throughout the body, and according to Dr. Hirsch, all of that inflammation may damage the nervous system. Another theory is that SARS-CoV-2 can injure the blood vessels that supply the brain with oxygen and nutrients, and when these get injured, it can lead to brain problems, said Dr. Al-Aly.
It’s also possible that the virus directly infects the neurological system and it can take some time for the brain and body to fully recover. “Additional research is needed to understand the mechanistic link between initial COVID infection and subsequent neurologic disease,” said Dr. Hirsch.
Researchers are also trying to identify who is most at risk for long COVID and, specifically, neurological complications.
Building evidence suggests that “people with co-morbidities like cardiovascular comorbidities (diabetes, obesity, etc) are at risk, but those comorbidities also place patients at risk for many neurologic diseases even without COVID,” said Dr. Hirsch.
Again, future studies will help inform our understanding of who’s most likely to develop neurological impairments after being diagnosed with COVID.
Regarding this new research, though the findings offer some evidence of a possible association between COVID and neurological disorders, it’s still too soon to draw any solid conclusions.
“The study helps us say there is a possible association between COVID and subsequent development of neurologic disorders,” Karen Hirsch, MD, a neurologist with Stanford Health Care, told Health. But “many details are still lacking,” she added, including more specificity about the diseases with a connection to COVID.
While the study looked at a large range of neurological conditions—from cognitive and memory disorders to nerve sensory disorders—it’s unclear if the symptoms were due to neurological disease or caused by some other health condition.
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COVID Prevention Methods Still Matter
The billion dollar question at this point is how to prevent both neurological and non-neurological symptoms after COVID, said Dr. Hirsch.
Of course, the best way to prevent post-covid symptoms is to avoid catching the virus in the first place—that means practicing CDC-recommended preventive measures in high-risk situations and staying up-to-date on vaccinations.
Vaccines specifically, while they can help prevent an acute case of COVID, may also provide some protection against long-term brain problems associated with COVID. A previous study led by Dr. Al-Aly found that vaccination can reduce the risk of Long COVID by about 20%, though vaccines shouldn’t be the only line of defense.
Once infected with COVID, there’s currently no concrete data supporting any particular approach, with the exception of the standard treatments and therapies, such as Paxlovid, that used to treat the infection itself.
Prevention or management of underlying health conditions is another effective mode of protection. “Stay healthy and active and work closely with your medical team to manage chronic conditions, and if long-term symptoms develop post-COVID, see a physician,” said Dr. Hirsch.
Though there’s still much more work to do in regards to post-COVID symptoms, future studies will hopefully give us the tools and knowledge necessary to help prevent millions of Americans from experiencing debilitating brain problems after COVID.
“We really need to understand mechanisms,” said Dr. Al-Aly. “We need to know how COVID affects brain health, and we need to figure out ways to prevent and treat these complications.”