Mild COVID increases risk of many neurological problems for millions

New research from the Washington University School of Medicine in St. Louis presents the most comprehensive investigation to date into the long-term neurological problems associated with COVID-19. Tracking more than 150,000 COVID patients for 12 months the research found infections led to a 42% increase in risk of several brain disorders.

Ziyad Al-Aly, an epidemiologist at Washington University, has been working with the US Department of Veterans Affairs since the pandemic began. The research uses massive healthcare databases to garner novel insights into the long-term effects of COVID-19.

Earlier in 2022, Al-Aly and colleagues published several studies reporting increases in cardiovascular problems and mental health disorders in COVID-19 patients up to 12 months after an initial infection. This new study, published in Nature Medicine, broadly looks at a variety of neurological problems in the year following mild and severe infections.

“Our study provides a comprehensive assessment of the long-term neurologic consequences of COVID-19,” explained Al-Aly. “Past studies have examined a narrower set of neurological outcomes, mostly in hospitalized patients. We evaluated 44 brain and other neurologic disorders among both nonhospitalized and hospitalized patients, including those admitted to the intensive care unit.”

The investigation included cerebrovascular events such as stroke, episodic disorders including migraine and seizure, and cognitive conditions like Alzheimer’s. Overall, the findings showed COVID survivors were 42% more likely to experience some kind of neurological problem in the year after an infection, compared to uninfected controls.

More specifically, the study reported COVID survivors faced a 77% increased risk of memory problems, 50% increased risk of stroke, 80% increased risk of seizure, and a 30% increased risk of eye problems. Echoing some prior studies, the researchers also saw small increases in Alzheimer’s diagnoses in COVID patients relative to uninfected controls.

“It’s unlikely that someone who has had COVID-19 will just get Alzheimer’s out of the blue,” Al-Aly stressed. “Alzheimer’s takes years to manifest. But what we suspect is happening is that people who have a predisposition to Alzheimer’s may be pushed over the edge by COVID, meaning they’re on a faster track to develop the disease. It’s rare but concerning.”

There are several caveats to these findings that are important to note. The cohort used in the research is old, with an average age of 61. And due to the long 12-month follow-up almost all of these initial infections were in unvaccinated subjects.

So it is possible these increased risks could be lessened in younger and/or vaccinated populations. However, Al-Aly does note some risks of specific neurological conditions were higher in younger people.

“Risks of memory and cognitive disorders, sensory disorders and disorders including Guillain–Barré and encephalitis or encephalopathy is stronger in younger adults,” Al-Aly said on Twitter. “… the effects of these disorders on younger lives are profound and cannot be overstated.”

It’s also crucial to stress the actual absolute increases in cases of these conditions were small. Overall, the study found seven extra cases of any neurological problem for every 100 COVID cases.

So, in real terms, these are small numbers, and potentially even smaller if age and vaccination make any kind of difference. But the researchers do make clear in the study that because this pandemic is so widespread, even tiny absolute numbers add up to a large volume of affected people.

“Given the colossal scale of the pandemic, and even though the absolute numbers reported in this work are small, these may translate into a large number of affected individuals around the world – and this will likely contribute to a rise in the burden of neurologic diseases,” the researchers reported in the study.

According to the researchers, if the numbers in this study were extrapolated to the amount of COVID cases reported in the US more than six million people will have experienced some kind of neurological problem in the year after infection. Even conservatively cutting that number in half still leaves millions of people facing brain challenges after COVID.

“The results show the devastating long-term effects of COVID-19,” said Al-Aly. “These are part and parcel of long COVID. The virus is not always as benign as some people think it is.”

The new study was published in Nature Medicine.

Source: Washington University School of Medicine in St. Louis