Microvascular remodeling and endothelial dysfunction across the post-COVID-19 spectrum: a prospective observational case-control study.
Wallraven, Timon, Günthner, Roman, Lethen, Isabelle et al.·BMC medicine·2026
Researchers studied blood vessel changes in the tiny vessels of the eye (using a technique called retinal vessel analysis) in people with post-COVID-19 syndrome and a subgroup meeting ME/CFS criteria, compared to people who recovered from COVID-19 and those never infected. People with post-COVID-19 syndrome, particularly those meeting ME/CFS criteria, showed narrower arteries and altered vessel patterns associated with worse symptoms and higher inflammation markers. While these findings are reported as preliminary observations, the relevance of post-COVID-19 vessel changes to ME/CFS specifically remains unclear, and this study does not yet establish whether such changes cause symptoms or could guide treatment.