A series of studies released over the last week have begun to shine a light on the impact of SARS-CoV-2 infection on brain function and cognitive health. The first study, published in Nature on March 7, compared brain scans from 401 individuals before and after SARS-CoV-2 infection. The initial brain scans were part of the UK Biobank that was collecting data before the pandemic began. Individuals were invited back for a second scan approximately 5 months after a SARS-CoV-2 infection. The study also had 384 SARS-CoV-2-negative controls. According to the study, individuals who had a SARS-CoV-2 infection lost between 0.2-2% more gray matter—mostly in areas associated with the sense of smell—than the control group. Additionally, individuals who had been infected had lower scores on cognitive function tests.
A second study, published March 8 in JAMA Neurology, examined cognitive health in a cohort of 1,438 COVID-19 patients who were 60 years and older and who were discharged from hospitals in Wuhan, China, during the first few months of the pandemic. The study found a 12.45% increase in cognitive impairment 12 months after discharge when compared to controls. The authors noted that 21% of individuals who experienced severe cases of COVID-19 experienced cognitive decline within 12 months.
A third study, posted March 7 in Open Forum Infectious Diseases, examined new-onset dementia in patients who experienced COVID pneumonia. According to the study, 3% of individuals who experienced COVID pneumonia developed new-onset dementia within 182 days compared with 2.5% of individuals who experienced pneumonia from other causes. Risk factors for new-onset dementia included ages 55 years and older, alcohol use or abuse, Hispanic race, history of depression, and stroke during COVID-19 hospitalization. Additional complications related to long COVID include cardiovascular issues and nerve damage.
A study published February 7 in Nature Medicine compared US Department of Veterans Affairs (VA) electronic health records from 150,000 patients who were infected with SARS-CoV-2 to millions of VA patients who did not have recorded infections. The study found a 4% increase in cardiovascular health issues in the SARS-CoV-2-positive individuals. Individuals who were hospitalized for COVID-19 were twice as likely to experience a significant cardiac event within 12 months of infection when compared to individuals who had milder cases of COVID-19.
Another study, published in Neurology Neuroimmunology & Neuroinflammation on March 1, examined data from patients diagnosed with long COVID who did not have a prior history of nerve dysfunction. The study found that long COVID may lead to long-lasting nerve damage and pain. The growing body of research on long COVID indicates that the world may experience a surge in chronic illness once the emergency phase of the pandemic winds down.
CSSE is reporting 79,455,416 positive cases in the U.S. and 965,468 deaths.