A study into the long-term health impacts of coronavirus, led by experts from the University of Leicester, Imperial College London and University College London, has found changes in the blood after COVID-19 that might pinpoint patients at risk of ongoing lung disease.
Led by the National Institute for Health and Care Research (NIHR) Leicester Biomedical Research Centre (BRC) the PHOSP-COVID study has drawn on expertise from a group of leading researchers and clinicians from across the UK to assess the impact of COVID-19 on patients’ physical and mental health, and their recovery.
In this latest study, published in EBioMedicine on 27 January 2026 (date) blood samples from almost 1,000 people who were hospitalised for COVID-19 were tested for molecules believed to be present when there is lung damage.
Patients who had evidence of lung changes on scans of their lungs were found to have higher levels of molecules known as ‘matrix metalloproteinase-7’ (MMP-7) and ‘Krebs von den Lungen-6 (KL-6) in their blood.
Both of these molecules have previously been shown to be elevated in individuals with diagnosed lung disease, and indicate damage to the epithelial cells that line the lungs.
Dr Rachael Evans, Clinical Associate Professor at the University of Leicester, said: “Epithelial cells form the crucial barrier lining the lungs, acting as the first defence against the particles we breathe in, producing mucus and initiating immune responses.
“The biomarkers we’ve observed in the blood samples in this study tell us that there is damage to this lining, and this is contributing to ongoing symptoms and restrictive lung function in some people with long-COVID.
“These findings could pave the way for simple blood tests to determine which individuals might have ongoing lung problems, and help us decide on the best course of treatment for them.”
Dr Iain Stewart from the National Heart & Lung Institute at Imperial College London, who led the analyses, said: “Because PHOSP‑COVID gathered such detailed, high‑quality information from so many people, we were able to uncover signs of ongoing lung damage even in a relatively small group. The fact that this damage may have life‑long consequences means that finding reliable markers to identify people at risk is crucial.”
Professor Louise Wain, who co-leads the PHOSP-COVID study at the University of Leicester, says “We are immensely grateful to the PHOSP-COVID study participants for giving up their time to provide information about their recovery and samples. Thanks to them, this research represents another step forward in identifying the specific underlying causes of ongoing symptoms after COVID-19 and helping doctors and patients to access appropriate and effective treatments.”
Professor Gisli Jenkins, from the National Heart & Lung Institute at Imperial College London, said: “These results highlight the possibility of using a blood test to identify people at increased risk of chronic lung disease following acute SARS-CoV-2 infection.”
Professor Rachel Chambers Professor of Respiratory Cell and Molecular Biology at University College London, said: “It has been a privilege to work with leading investigators across the UK and contribute to this PHOSP-COVID consortium study.
“These findings represent an exciting step forward in identifying reliable markers to monitor patients with ongoing lung damage.”