MicroRNAs in Long COVID: Key Regulators, Biomarkers, and Therapeutic Targets of Post-SARS-CoV-2 Sequelae

COVID, or post-acute sequelae of SARS-CoV-2 infection (PASC), is clinically defined by persistent symptoms that endure beyond acute infection and affect multiple organ systems, including the immune, cardiopulmonary, neurological, and metabolic axes. The underlying mechanisms remain poorly resolved, limiting the development of targeted diagnostics and therapeutics. MicroRNAs (miRNAs), as key post-transcriptional regulators of gene expression, control inflammatory networks, antiviral responses, mitochondrial bioenergetics, and fibrotic pathways, all of which are implicated in long COVID pathogenesis. Recent studies show durable changes in circulating miRNA signatures months after recovery from the acute phase, suggesting a role in maintaining chronic immune activation and metabolic dysfunction. Importantly, circulating miRNAs are stable, quantifiable in biofluids, and reflect systems-level dysregulation, positioning them as promising biomarker candidates for patient stratification, symptom clustering, and disease monitoring. Moreover, miRNA-directed interventions, such as mimics and antagomiRs, represent an emerging precision-medicine strategy to correct sustained molecular disturbances. This review summarizes current evidence linking miRNAs to long COVID, highlights their biomarker potential, and discusses therapeutic avenues that may help advance mechanism-based interventions for this globally emerging chronic condition.