Additional support for the hypothesis that ME/CFS may represent a poly-herpesvirus syndrome comes from several double-blind, placebo-controlled studies demonstrating that long-term therapy (6 months) with the herpesvirus-targeting antivirals valaciclovir or valganciclovir led to improved clinical symptoms and reduced serum antibody titers among ME/CFS patients infected with EBV or with combinations of EBV, HCMV, and HHV-6 [98,106,107,108,109,110,111].
98 - Kasimir, F.; Toomey, D.; Liu, Z.; Kaiping, A.C.; Ariza, M.E.; Prusty, B.P. Tissue specific signature of HHV-6 infection in ME/CFS. Front. Mol. Biosci.
2022, 9, 1044964. [
Google Scholar] [
CrossRef]
106 - Lerner, A.M.; Beqaj, S.H.; Deeter, R.G.; Dworkin, H.J.; Zervos, M.; Chang, C.H.; Fitzgerald, J.T.; Goldstein, J.; O’Neill, W. A six-month trial of valacyclovir in the Epstein-Barr virus subset of myalgic encephalomyelitis/chronic fatigue syndrome: Improvement in left ventricular function. Drugs Today
2002, 38, 549–561. [
Google Scholar]
107 - Lerner, A.M.; Beqaj, S.H.; Deeter, R.G.; Fitzgerald, J.T. Valacyclovir treatment in Epstein-Barr virus subset chronic fatigue syndrome; thirty-six months follow-up. In Vivo
2007, 21, 707–714. [
Google Scholar]
108 - Lerner, A.M.; Beqaj, S.; Fitzgerald, J.T.; Gill, K.; Gill, C.; Edington, J. Subset-directed antiviral treatment of 142 herpesvirus patients with chronic fatigue syndrome. Virus Adapt. Treat.
2010, 2, 47–57. [
Google Scholar]
109 - Kogelnik, A.M.; Loomis, K.; Hoegh-Petersen, M.; Rosso, F.; Hischier, C.; Montoya, J.G. Use of valganciclovir in patients with elevated antibody titers against human herpesvirus-6 (HHV-6) and Epstein-Barr virus (EBV) who were experiencing central nervous system dysfunction including long-standing fatigue. J. Clin. Virol.
2006, 73, S33–S38. [
Google Scholar] [
CrossRef] [
PubMed]
110 - Watt, T.; Oberfoell, S.; Balise, R.; Lunn, M.R.; Kar, A.K.; Merrihew, L.; Bhangoo, M.S.; Montoya, J.G. Response to valganciclovir in chronic fatigue syndrome patients with human herpesvirus 6 and Epstein-Barr virus IgG antibody titers. J. Med. Virol.
2012, 84, 1967–1974. [
Google Scholar] [
PubMed]
111 - Montoya, J.G.; Kogelnik, A.M.; Bhangoo, M.; Lunn, M.R.; Flamand, L.; Merrihew, L.E.; Watt, T.; Kubo, J.T.; Paik, J.; Desai, M. Randomized clinical trial to evaluate the efficacy and safety of valganciclovir in a subset of patients with chronic fatigue syndrome. J. Med. Virol.
2013, 85, 2101–2109. [
Google Scholar] [
CrossRef] [
PubMed]
Skimming the last study by Montoya:
There are minuscule differences between the groups in subjective outcomes. Most were not statistically significant, and those that were are probably not clinically meaningful. The original primary outcome was not met. It was funded by the owner of the drug, Roche.
If that is representative for the rest of the references, there is not much to go on here.