Even Mild COVID Cases May Cause Damage in the Brain, Study Suggests

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Key TakeawaysA new study suggests even mild cases of Covid-19 can cause changes in the brain.Researchers examined brain scans to determine that those who’d been infected with Covid-19 showed greater loss of gray matter and abnormalities in brain tissue.While the findings are important, further research must be conducted to understand the long-term effects of Covid-19 on the brain.

Key Takeaways

A new study suggests even mild cases of Covid-19 can cause changes in the brain.Researchers examined brain scans to determine that those who’d been infected with Covid-19 showed greater loss of gray matter and abnormalities in brain tissue.While the findings are important, further research must be conducted to understand the long-term effects of Covid-19 on the brain.

As the United States approaches nearly 80 million Covid-19 cases since the start of the pandemic,it’s likely that you, or someone you know, has had it at some point. And while we know the symptoms' impact in the short-term, the virus' lasting effects still remain somewhat of a mystery.

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The Research

The researchers examined brain scans of 401 individuals who’d been infected with Covid-19 between March 2020 and May 2021. The scans were taken before infection and about 4.5 months following infection.

When compared to brain scans from 384 individuals who hadn’t contracted Covid-19, those who’d had the virus showed greater loss of gray matter and damage to brain tissue. These differences were found mainly in the areas of the brain that deal with our sense of smell.

Gwenaëlle Douaud, PhDA key question for future brain imaging studies is to see if this brain tissue damage resolves over the longer term.

Gwenaëlle Douaud, PhD

A key question for future brain imaging studies is to see if this brain tissue damage resolves over the longer term.

The scans also revealed that overall brain size decreased in participants who’d been infected, as well. These findings were more prominent in older participants.

“They also showed greater decline in their mental abilities to perform complex tasks, and this mental worsening was partly related to these brain abnormalities,” said lead study author Gwenaëlle Douaud, PhD, in a statement. “All these negative effects were more marked at older ages. A key question for future brain imaging studies is to see if this brain tissue damage resolves over the longer term.”

Stephen SmithThe fact that we have the pre-infection scan helps us distinguish brain changes related to the infection from differences that may have pre-existed in their brains.

Stephen Smith

The fact that we have the pre-infection scan helps us distinguish brain changes related to the infection from differences that may have pre-existed in their brains.

The data used for the study was collected from a government health database, the UK Biobank. Participants, whose ages fell between 51-81, underwent two brain scans about 38 months apart. The scan taken prior to infection has special significance, said senior study author Stephen Smith in a release.

“The fact that we have the pre-infection scan helps us distinguish brain changes related to the infection from differences that may have pre-existed in their brains,” Smith said.

Even Mild COVID Cases May Cause Damage in the Brain, Study Suggests

A Better Understanding

“This study highlights that even non-brain infections and inflammation, in general, can have lasting deleterious effects in the body including brain injury, atrophy, and dementia,” says neurologistSantosh Kesari, MD, PhD, regional medical director for the Research Clinical Institute of Providence Southern California.

While previous research has linked Covid-19 to inflammation as a potentialcause for damageto the brain,Naomi Allen, chief scientist at the UK Biobank, noted in a release that this particular study is extremely rare in demonstrating a “before vs. after” depiction of the brain in relation to Covid-19.

“Collecting a second set of multi-organ imaging scans from some people who had been infected with SARS-CoV-2 and from others who had not been infected has generated a unique resource to enable scientists to understand how the virus affects internal organs,” Allen said,

As a normal part of the aging process, our brains lose a little gray matter each year.And while study participants showed slightly greater loss in gray matter,researchers are still unsure as to whether that could impact function and quality of life.

While these findings are important, the long-term effects of Covid-19 are still unknown and further research is necessary.

What This Means For YouAlthough this study found that even a mild case of Covid-19 can impact the brain, there’s no reason to panic. Long-term effects of the virus are yet to be fully understood.

What This Means For You

Although this study found that even a mild case of Covid-19 can impact the brain, there’s no reason to panic. Long-term effects of the virus are yet to be fully understood.

4 SourcesVerywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.The New York Times.Coronavirus in the U.S.: Latest map and case count.Douaud G, Lee S, Alfaro-Almagro F, et al.SARS-CoV-2 is associated with changes in brain structure in UK Biobank.Nature. 2022. doi:10.1038/s41586-022-04569-5Spudich S, Nath A.Nervous system consequences of COVID-19.Science. 2022;375(6578):267-269. doi:10.1126/science.abm2052Hafkemeijer A, Altmann‐Schneider I, de Craen AJM, Slagboom PE, van de Grond J, Rombouts SA.Associations between age and gray matter volume in anatomical brain networks in middle‐aged to older adults.Aging Cell. 2014;13(6):1068-1074. doi:10.1111/acel.12271

4 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.The New York Times.Coronavirus in the U.S.: Latest map and case count.Douaud G, Lee S, Alfaro-Almagro F, et al.SARS-CoV-2 is associated with changes in brain structure in UK Biobank.Nature. 2022. doi:10.1038/s41586-022-04569-5Spudich S, Nath A.Nervous system consequences of COVID-19.Science. 2022;375(6578):267-269. doi:10.1126/science.abm2052Hafkemeijer A, Altmann‐Schneider I, de Craen AJM, Slagboom PE, van de Grond J, Rombouts SA.Associations between age and gray matter volume in anatomical brain networks in middle‐aged to older adults.Aging Cell. 2014;13(6):1068-1074. doi:10.1111/acel.12271

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

The New York Times.Coronavirus in the U.S.: Latest map and case count.Douaud G, Lee S, Alfaro-Almagro F, et al.SARS-CoV-2 is associated with changes in brain structure in UK Biobank.Nature. 2022. doi:10.1038/s41586-022-04569-5Spudich S, Nath A.Nervous system consequences of COVID-19.Science. 2022;375(6578):267-269. doi:10.1126/science.abm2052Hafkemeijer A, Altmann‐Schneider I, de Craen AJM, Slagboom PE, van de Grond J, Rombouts SA.Associations between age and gray matter volume in anatomical brain networks in middle‐aged to older adults.Aging Cell. 2014;13(6):1068-1074. doi:10.1111/acel.12271

The New York Times.Coronavirus in the U.S.: Latest map and case count.

Douaud G, Lee S, Alfaro-Almagro F, et al.SARS-CoV-2 is associated with changes in brain structure in UK Biobank.Nature. 2022. doi:10.1038/s41586-022-04569-5

Spudich S, Nath A.Nervous system consequences of COVID-19.Science. 2022;375(6578):267-269. doi:10.1126/science.abm2052

Hafkemeijer A, Altmann‐Schneider I, de Craen AJM, Slagboom PE, van de Grond J, Rombouts SA.Associations between age and gray matter volume in anatomical brain networks in middle‐aged to older adults.Aging Cell. 2014;13(6):1068-1074. doi:10.1111/acel.12271

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