Chronic Fatigue Syndrome often occurs following a viral infection, sometimes after a bacterial infection, or after the body experiences trauma such as undergoing a surgical procedure. It is believed that an immune dysregulation is the cause of its occurrence following an infection or trauma. One example of this is Long COVID.

As an illustration of the impact of viral infection in triggering Chronic Fatigue Syndrome: millions of people worldwide have suffered from various symptoms since the COVID-19 pandemic, which are either similar to or different from the original illness. Patients frequently describe these symptoms as “strange,” energy-depleting, and fluctuating in many – though not all – cases. Regarding specific symptoms, the review identifies a wide range that spans multiple organ systems, including: shortness of breath, chest pain, cognitive impairment, loss of taste and smell, severe fatigue, muscle and joint pain, gastrointestinal disturbances, headaches, and skin rashes. Among these symptoms, fatigue is a pivotal feature; it is a common symptom in Long COVID and typically worsens after physical exertion.

Furthermore, the prevalence figures for both conditions vary and are difficult to quantify precisely. The number of people affected by chronic fatigue reaches about one in every 150 individuals, which is less than 1%. As for Long COVID, the percentage of people who experienced lingering symptoms after their infection reached up to 6% in the United States, according to one study. What unites both conditions and prompted us to bring them together in a single article is that fatigue is the most prominent characteristic, alongside cognitive issues such as memory impairment.

It is worth noting that recent studies group the two conditions together in an effort to understand what is happening, considering Long COVID to be either a subset of Chronic Fatigue Syndrome or an identical condition, but with the definitive knowledge that its trigger is linked to a viral infection.

This article is part of a series of articles on Chronic Fatigue Syndrome.