Postviral fatigue syndrome

Postviral Fatigue Syndrome (PVFS) refers to a post-infectious fatiguing illness with many similarities to myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Since not all cases of ME or CFS are preceded by a viral infection, the term PVFS has become outdated and is nowadays seldom used in scientific literature. As ME-expert Peter Behan explained these developments: “It became abundantly, crystal clear that several patients had developed the syndrome, the identical syndrome but they had developed the syndrome not following a viral or other infection but due to their reaction to a particular form of stress.”

ICD-10 title:
Postviral fatigue syndrome is the official concept title of code G93.3 in the ICD-10, the medical classification list of the World Health Organization (WHO). 'Benign myalgic encephalomyelitis' is inscribed as an inclusion, while 'chronic fatigue syndrome' is listed only in the index. Since postviral fatigue syndrome is seldom used in scientific research and clinical practice, some argue it should be removed as a concept title. Mary Dimmock and Suzy Chapman for example propose to list PVFS in the upcoming ICD-11 as a synonym term under a new concept title "Myalgic encephalomyelitis." In parallel, the IACFS/ME submitted a proposal to the CDC regarding the ICD-10-CM, which is used in the US. This suggests the concept title PVFS be expanded to also include the terms "chronic fatigue syndrome" (CFS) and "myalgic encephalomyelitis" (ME). The proposal recommends all three terms be added as subcodes, each with unique code. Both proposals recommend these three terms be maintained in the neurological chapter.

Post-infectious Fatigue Syndrome
The Oxford criteria has a Post-infectious Fatigue Syndrome (PIFS) as one of its definitions. The Argus Report article US NIH Report Calls for UK Definition of ME/CFS to be Scrapped states: "The NIH has issued a draft report that highlights the dire need for scientific research that will help find a cure for the millions of people suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) worldwide. The report also highlights the fact that the decades-old UK Royal Society of Medicine’s Oxford criteria for ME/CFS are severely “flawed,” and that continuing to use these criteria may “cause harm.” Further, the NIH report says that the Royal Society definition should “be retired” and replaced with a single case definition agreed to by the ME/CFS community."