Long COVID: Mechanisms, Biomarkers, and Treatment

Dear Colleagues,

Prolonged symptoms post-SARS-CoV-2 infection are appearing at the alarming rate of 10–15% worldwide. These post-infection sequalae, widely termed long COVID (LC) or post-acute sequalae of COVID-19 (PACS), include a wide range of profiles of overlapping symptoms persisting for more than 12 weeks, with debilitating fatigue as the main one, associated with cognitive impairment, and many more, notably pain and postural orthostatic tachycardia (POTS)-like symptoms. An official definition of LC was released in 2021, but LC is perceived, diagnosed, and managed in many different ways across the world, with very few policies, consensus, or guidelines between the many disciplines involved.

Chronic fatigue does not ameliorate with time and, most importantly, if not resolved within the first 6 months, it may never resolveA wide range of biological disturbances have been associated with chronic fatigue and, as such, many hypotheses have been proposed, but the causative mechanisms remain unknown. Due to this lack of mechanistic insight into the causes and pathological events, no effective drug/intervention exists for LC. Furthermore, it is crucial to establish whether LC has a unique mechanism leading to chronic fatigue with potentially a universal treatment or if it represents a combination of symptoms with different mechanisms that culminate in fatigue but need alternative types of treatments. In fact, most of the proposed mechanisms for LC may not be mutually exclusive and they may overlap; alternatively, different mechanisms may develop in specific subgroups of patients. This will have a large impact on defining how rehabilitation, pharmaceutical, and lifestyle therapeutic strategies can reduce the personal/societal burden of this devastating condition.

The Special Issue invites manuscripts related to all aspects of long COVID research, including clinical, mechanistic, biomarkers, and treatment strategies.

Dr. Frédérique Ponchel
Guest Editor

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• long-COVID
• clinical observations
• disease mechanism
• biomarkers
• treatment strategies
• opinions