The covid-19 pandemic may have accelerated the ageing of our brains even before we caught the infection. Research suggests that even relatively early on in the outbreak, brains aged by 5.5 months, possibly due to stress or lifestyle changes. We know that many people with long covid experience brain fog, but years after the arrival of covid-19, the pandemic's broader neurological impact is far from fully understood. To get a grasp on this, Ali-Reza Mohammadi-Nejad at Nottingham University, UK, and his colleagues trained a machine learning model on 15,000 brain scans to identify how its structure changes with age. They then fed the model pairs of brain scans from 996 volunteers from the UK Biobank study.