Patient perceptions of infectious illnesses preceding Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Chronic Illn. 2022 Dec;18(4):901-910. doi: 10.1177/17423953211043106. Epub 2021 Sep 20.


Objectives: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is often reported to be caused by an infectious agent. However, it is unclear whether one infectious agent might be the cause or whether there might be many different infectious agents. The objective of this study was to identify self-reported infectious illnesses associated with the onset of ME/CFS.

Methods: The present study involved data from multiple sites in several countries. 1773 individuals diagnosed with either ME, CFS or ME/CFS provided qualitative data concerning infectious triggers which were coded and classified for analysis.

Results: 60.3% of patients report a variety of infectious illnesses some time before onset of ME/CFS. The most frequently reported infectious illness was Mononucleosis, which occurred in 30% of infections. However, over 100 other infectious illnesses were mentioned.

Discussion: The findings suggest that many infectious agents might be associated with the onset of ME/CFS.

Keywords: Chronic fatigue syndrome; ME/CFS; infectious illness; mononucleosis; myalgic encephalomyelitis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Fatigue Syndrome, Chronic*
  • Humans
  • Self Report