Mild-to-Moderate Cognitive Deficits Persist After COVID-19

Infection with SARS-CoV-2 can produce microvascular damage and neuroinflammation. Longitudinal studies of cognition and brain gray matter volume — some of which included measurements taken before and after the pandemic — have shown that even people with mild acute COVID-19 experience some loss of cognitive capacity and of gray matter compared with those who did not have COVID-19 (NEJM JW Gen Med Jun 1 2022 and Nature 2022; 604:697).

English investigators invited 800,000 people to complete an online cognitive test battery; 14% completed it. Compared with people who did not contract COVID-19, those with COVID-19 had measurable deficits that correlated with patients' statements about cognitive difficulties. In analyses adjusted for potentially confounding factors, the measured deficits were as follows:

• Greatest (equating to ≈6 points on an IQ test) in those with cognitive symptoms that persisted beyond 12 weeks and in those the most severe acute illness

• Somewhat smaller in those whose symptoms resolved within 12 weeks

• Detected even in asymptomatic infected people

• Less likely in people who contracted COVID-19 later in the pandemic, when new SARS-CoV-2 variants were circulating and when vaccines and therapies were available, particularly in those who had received at least two vaccinations