Iron Dysregulation Identified as Key Trigger for Long COVID
New research suggests that problems with iron levels in the blood and the body's ability to regulate this nutrient following SARS-CoV-2 infection could be a key trigger for long COVID. This discovery offers potential avenues for prevention or treatment and may explain similar symptoms observed in other post-viral conditions and chronic inflammation.
Problems with iron levels and the body's ability to regulate this nutrient following SARS-CoV-2 infection could be a key trigger for long COVID.
Long COVID: A Widespread Concern
As many as three in ten individuals infected with SARS-CoV-2 may develop long COVID, characterized by symptoms such as fatigue, shortness of breath, muscle aches, and cognitive issues. Data from March 2023 indicated approximately 1.9 million people in the UK reported experiencing long COVID.
The Study: Tracking Post-Infection Changes
Researchers from the University of Cambridge and Oxford, as part of the NIHR BioResource, recruited individuals who tested positive for SARS-CoV-2 early in the pandemic. They collected blood samples over a year, tracking changes post-infection. As long COVID cases emerged, researchers correlated blood changes with later symptoms.
The study, published in Nature Immunology, analyzed blood samples from 214 individuals. Approximately 45% of participants reported long COVID symptoms between three and ten months post-infection.
Key Discovery: Early Iron Dysregulation
The team identified ongoing inflammation and low blood iron levels, contributing to anaemia and disrupting red blood cell production, as early as two weeks after COVID-19 in individuals who later reported long COVID. This early iron dysregulation was observed regardless of age, sex, or initial COVID-19 severity.
Expert Perspectives on Iron's Role
Dr. Aimee Hanson noted that iron levels and regulation were disrupted early in SARS-CoV-2 infection and took a long time to recover, particularly in those who developed long COVID. Although the body attempted to rectify low iron availability, it struggled due to persistent inflammation.
Professor Hal Drakesmith explained that iron dysregulation is a common inflammatory response to infection, where iron is removed from the bloodstream to protect against pathogens. However, prolonged removal reduces iron available for red and white blood cells, impairing oxygen transport and immune function. This mechanism may explain common long COVID symptoms like fatigue and exercise intolerance.
Avenues for Prevention and Treatment
The findings suggest potential strategies to prevent or reduce long COVID's impact by addressing iron dysregulation early in the infection. This could involve controlling inflammation or iron supplementation. Dr. Hanson cautioned that supplementation is complex, as the issue may involve trapped iron rather than an overall deficiency, requiring methods to remobilize it.
Broader Implications and Funding
Supporting evidence comes from other studies, including the IRONMAN study on heart failure patients, which incidentally suggested trial participants had a lower risk of severe COVID-19 effects. Similar observations have been made in individuals with beta-thalassemia, a blood disorder causing excess iron. The research received funding from Wellcome, the Medical Research Council, NIHR, and the European Union Horizon 2020 Programme.