Chia, J K, Chia, L Y · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 1999 · DOI
This study examined whether a common bacterial infection called Chlamydia pneumoniae might be a treatable cause of ME/CFS. Researchers looked at patients with ME/CFS and tested whether treating this infection with antibiotics could improve their symptoms. The authors suggest that some cases of ME/CFS might be linked to this persistent bacterial infection.
Understanding potential infectious triggers for ME/CFS could identify treatable subgroups of patients and guide therapeutic approaches. If confirmed, this association might lead to specific antimicrobial interventions that could benefit some ME/CFS patients who have been difficult to treat.
This study does not prove that Chlamydia pneumoniae causes ME/CFS in all or most patients, nor does it establish that antibiotic treatment is effective for the broader ME/CFS population. The observational design means results cannot determine causation and may reflect selection bias or placebo effects rather than true biological relationships.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Chia, J K & Chia, L Y (1999). Chronic Chlamydia pneumoniae infection: a treatable cause of chronic fatigue syndrome.. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. https://doi.org/10.1086/520239
BibTeX
@article{mecfsatlas-chia-1999-chronic-chlamydia,
author = {Chia, J K and Chia, L Y},
title = {Chronic Chlamydia pneumoniae infection: a treatable cause of chronic fatigue syndrome.},
journal = {Clinical infectious diseases : an official publication of the Infectious Diseases Society of America},
year = {1999},
doi = {10.1086/520239},
note = {PubMed: 10476765},
url = {https://www.mecfsatlas.com/evidence/chia-1999-chronic-chlamydia},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/chia-1999-chronic-chlamydia
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