Bertram, G, Dreiner, N, Krueger, G R et al. · In vivo (Athens, Greece) · 1991
This study looked at 215 patients with infectious mononucleosis to see which viruses were causing their illness. Researchers found that most patients had Epstein-Barr virus (EBV), but many also had human herpesvirus-6 (HHV-6) at the same time. About 40% of patients had active infection with both viruses, and some had a third virus (CMV) as well. Patients were followed for two years to track changes in their virus levels.
This study is relevant to ME/CFS research because it documents that HHV-6 reactivation commonly occurs during acute infectious mononucleosis and that persistent HHV-6 infection may accompany post-infectious chronic fatigue syndrome in over 60% of cases. Understanding herpesvirus coinfection patterns during acute illness may help explain why some people develop prolonged fatigue after infection.
This study does not establish that HHV-6 causes ME/CFS or post-infectious chronic fatigue syndrome—it only shows correlation between HHV-6 presence and these conditions. The cross-sectional design cannot determine causality or whether HHV-6 reactivation is a cause or consequence of immune dysregulation. The study also does not explain why some patients with dual infection recover while others develop chronic fatigue.
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
Bertram, G, Dreiner, N, Krueger, G R, Ramon, A, Ablashi, D V, Salahuddin, S Z, et al. (1991). Frequent double infection with Epstein-Barr virus and human herpesvirus-6 in patients with acute infectious mononucleosis.. In vivo (Athens, Greece). https://pubmed.ncbi.nlm.nih.gov/1654150/
BibTeX
@article{mecfsatlas-bertram-1991-frequent-double,
author = {Bertram, G and Dreiner, N and Krueger, G R and Ramon, A and Ablashi, D V and Salahuddin, S Z and Balachandram, N},
title = {Frequent double infection with Epstein-Barr virus and human herpesvirus-6 in patients with acute infectious mononucleosis.},
journal = {In vivo (Athens, Greece)},
year = {1991},
note = {PubMed: 1654150},
url = {https://www.mecfsatlas.com/evidence/bertram-1991-frequent-double},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/bertram-1991-frequent-double
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