COVID raises risk of long-term brain injury, large US study finds

• Study assesses brain health across 44 different disorders using medical records.
• Says brain impairments in roughly 6.6 million Americans linked with their COVID infections.
• Shows people infected with virus also were 50% more likely to have ischemic stroke. 

People who had COVID-19 are at higher risk for a host of brain injuries a year later compared with people who were never infected by the coronavirus, a finding that could affect millions of Americans, according to US researchers.

A year-long study, published in Nature Medicine, assessed brain health across 44 different disorders using medical records without patient identifiers from millions of US veterans.

Brain and other neurological disorders occurred in 7% more of those who had been infected with COVID compared with a similar group of veterans who had never been infected. That translates into roughly 6.6 million Americans who had brain impairments linked with their COVID infections, the team said.

"The results show the devastating long-term effects of COVID-19," senior author Dr. Ziyad Al-Aly of Washington University School of Medicine said in a statement.

Al-Aly and colleagues at Washington University School of Medicine and the Veterans Affairs St. Louis Health Care System studied medical records from 154,000 US veterans who had tested positive for COVID from March 1, 2020 to January 15, 2021.

They compared these with records from 5.6 million patients who did not have COVID during the same time frame, and another group of 5.8 million people from the period just before the coronavirus arrived in the United States.

Al-Aly said prior studies looked at a narrower group of disorders, and were focused largely on hospitalised patients, whereas his study included both hospitalised and non-hospitalised patients.

Memory impairments, commonly referred to as brain fog, were the most common symptom. Compared with the control groups, people infected with COVID had a 77% higher risk of developing memory problems.

People infected with the virus also were 50% more likely to have an ischemic stroke, which is caused by blood clots, compared with the never-infected group.

Those who had COVID were 80% more likely to have seizures, 43% more likely to have mental health issues, such as anxiety or depression, 35% more likely to have headaches and 42% more likely to suffer movement disorders, such as tremors, compared with the control groups.

Researchers said governments and health systems must devise plans for a post-COVID world.

“Given the colossal scale of the pandemic, meeting these challenges requires urgent and coordinated - but, so far, absent - global, national and regional response strategies,” Al-Aly said.