Jose Montoya and Martin Lerner, have published previous studies suggesting that
valganciclovir therapy may be effective for the subset of CFS patients suspected of having smoldering or low-level infections of HHV-6, EBV and CMV.
http://hhv-6foundation.org/associated-conditions/hhv-6-and-chronic-fatigue-syndrome
take care, and let me know if you have any questions.