I had CMV, but my husband (recipient) did not. They knew when I donated it was not a matter of "if" but "when" he would get it. It is not common, as the vast majority of people have had CMV when they are children, but it happens more often than you would think. Since they could not control the "if" they controlled the "when". He was on Valcyte for 9 months to control the onset. The farther out you are from transplant, the better able to handle the virus.
When he stopped the Valcyte 9 months later, sure enough, within a couple weeks he began with extreme tiredness and a slight fever. They did a blood test and there it was. They began the Valcyte again, but when it was stopped, the CMV reared its ugly head again. They ended up juggling his anti rejection meds until a balance was reached where there was enough to prevent rejection, yet not so much for the CMV to pop out again. It took a few months for it all to be figured out.
I am glad to hear your recipient is doing better and that the CMV is now undetectable.