I was in a period of significant decline when I first began the Zovirax. The Zovirax definitely gave me an immediate boost, with little or no side effects, and within a couple of months I returned to what had been my long term baseline. Beyond that time frame the Zovirax appeared to do nothing, and switching to Valtrex did nothing but increase the side effects, so I stopped both entirely and saw no difference whatsoever.
In retrospect, I suspect that my overall viral load had gotten out of hand and was responsible for the significant decline that I was in...then the Zovirax helped reduce my viral load, and I went back to baseline. I don't see any chance that Zovirax, Valtrex, or any other antiviral was ever going to fix my underlying "CFS". This seems to fit the theory that while a virus may be responsible for "causing" CFS, it probably isn't responsible for maintaining it. Or, the virus is now inhabiting a place that isn't accessible to current antivirals.