Though Covid-19 cases have receded from the pandemic peak across the world, conditions such as long Covid and other consequences are plaguing several survivors. It is a matter of concern that those who have been infected with the virus are at increased risk of developing a range of neurological conditions in the first year after the infection, as revealed by a new research. Such complications include strokes, cognitive and memory problems, depression, anxiety and migraine headaches, according to a comprehensive analysis of US health data by researchers at Washington University School of Medicine in St Louis and the Veterans Affairs St Louis Health Care system.
The findings published September 22 in Nature Medicine explain that the post-Covid brain is associated with movement disorders, hearing and vision abnormalities, and balance and co-ordination difficulties as well as other symptoms similar to what is experienced with Parkinson’s disease. While past studies have examined a narrower set of neurological outcomes, mostly in hospitalised patients, senior author Dr Ziyad al-Aly, a clinical epidemiologist at Washington University, and colleagues evaluated 44 brain and other neurologic disorders among both nonhospitalised and hospitalised patients, including those admitted to the intensive care unit. The results show the devastating long-term effects of Covid-19.
Covid-19 has contributed to more than 40mn new cases of neurological disorders worldwide, pointed out Dr al-Aly. “We’re seeing brain problems in previously healthy individuals and those who have had mild infections,” he said. Few people in the study were vaccinated for Covid-19 because the vaccines were not yet widely available during the time span of the study, from March 2020 through early January 2021. The data also predates Delta, Omicron and other Covid variants. A previous study in Nature Medicine led by Dr al-Aly found that vaccines slightly reduce — by about 20% — the risk of long-term brain problems.
The researchers analysed about 14mn de-identified medical records in a database maintained by the US Department of Veterans Affairs, the nation’s largest integrated health-care system. Patients included all ages, races and sexes. They created a controlled data set of 154,000 people who had tested positive for Covid-19 sometime from March 1, 2020, through January 15, 2021, and who had survived the first 30 days after infection. Statistical modelling was used to compare neurological outcomes in the Covid-19 data set with two other groups of people not infected with the virus: a control group of more than 5.6mn patients who did not have Covid-19 during the same time frame; and a control group of more than 5.8mn people from March 2018 to December 31, 2019, long before the virus infected and killed millions across the globe.
The researchers examined brain health over a year-long period. Neurological conditions occurred in 7% more people with Covid-19 compared with those who had not been infected with the virus. People who contracted the virus were at a 77% increased risk of developing memory problems. Also compared to the control groups, people who had the virus were 50% more likely to suffer from an ischemic stroke. Overall, people who had Covid-19 were 80% more likely to suffer from epilepsy or seizures, 43% more likely to develop mental health disorders such as anxiety or depression, 35% more likely to experience mild to severe headaches, 42% more likely to encounter movement disorders, 30% more likely to have eye problems such as blurred vision, dryness and retinal inflammation; and 22% more likely to develop hearing abnormalities such as tinnitus, or ringing in the ears.
Long Covid’s effects on the brain and other systems emphasise the need for governments and health systems to develop policy, and public health and prevention strategies to manage the ongoing pandemic and devise plans for a post-Covid world.