Long COVID Study Links Fatigue to Mitochondrial Dysfunction

Researchers have identified persistent mitochondrial dysfunction and immune dysregulation as recurring biological features of long COVID, offering new clues about why symptoms such as fatigue, exercise intolerance, brain fog, and muscle weakness can linger long after the initial infection has resolved. 

In a new multi-omics study published in Frontiers in Immunology, scientists analyzed transcriptomic, proteomic, and metabolomic data from both human cohorts and animal models.

Across multiple tissues, they found evidence of ongoing suppression of oxidative phosphorylation (OXPHOS), the process by which mitochondria generate most of the body’s cellular energy.

The most persistent abnormalities were seen in skeletal muscle, where mitochondrial dysfunction remained detectable months after infection and was associated with fatigue-related changes. 

The researchers also observed signs of continued immune activation, oxidative stress, and metabolic abnormalities in blood and serum samples collected up to two years after infection. Patients with long COVID showed evidence of persistent inflammatory signaling and incomplete recovery of normal energy metabolism compared with individuals who had fully recovered. 

The findings are particularly notable because long COVID shares many symptoms with conditions such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), fibromyalgia, and postural orthostatic tachycardia syndrome (POTS).

The authors propose that ongoing mitochondrial dysfunction may contribute to a cycle of chronic immune activation and impaired recovery in some individuals. 

While the study does not prove that mitochondrial dysfunction causes long COVID, it adds to growing evidence that persistent biological changes may underlie many long-term symptoms and could eventually help guide future treatments. 

Citation

Tasoula A, Arif S, Waisberg E, Bauer L, Aslinger E and Guarnieri JW (2026) Multi-omics analysis of long COVID (post-COVID-19 condition) reveals persistent mitochondrial dysfunction, suppressed oxidative phosphorylation, and immune dysregulation. Front. Immunol. 17:1776555. doi: 10.3389/fimmu.2026.1776555