Anyone who had Covid could have disease ‘signature’ in their blood

Anyone who had Covid could have disease ‘signature’ in their bloodScientists have discovered a lasting legacy of the pandemicCommentsNewsSamantha Leathers Senior Money & Lifestyle writer13:23, 20 Apr 2026View 3 ImagesScientists discovered a 'signature' of the infection in long Covid patients(Image: GETTY)A new study has discovered a “signature” of Covid in the blood of some people who had fallen ill with the virus. Blood tests showed the mark remained even months after the initial infection.‌Researchers in Australia and Norway are trying to figure out why some people developed long Covid during the pandemic while others fully recovered from the illness. Long Covid occurs when the symptoms of Covid last longer than 12 weeks.‌Some people may struggle with the condition for several years, characterised by persistent symptoms like fatigue, breathlessness and brain fog. There’s currently no cure for the condition and how it operates is still a mystery for medical professionals.‌The new study revealed that protein patterns linked to long Covid could be found in the blood of infected people several months after their initial infection, described as a ‘distinct immune signature in the blood’ by experts at News Medical.View 3 ImagesScientists are trying to figure out why some people fully recovered from Covid and others didn't(Image: GETTY)Published in the Communications Medicine journal, researchers focused on inflammatory and neurological protein changes between different people and monitored how these reacted to vaccination and reinfection.‌The study involved three groups of people in Victoria, Australia:People that didn’t have CovidPeople that had Covid and recovered fullyPeople with long CovidThey collected blood samples from participants six to nine months after initial infection and before vaccination. Both groups that had been ill with Covid had experienced changes in their immune-related proteins compared to those that had never been sick.‌After v...