The only thing in the Wilson article that I paused at was "REOLYSIN only induces mild symptoms that resemble influenza. It is worrisome that this therapeutic would be used in patients with compromised immune systems, but the reovirus seems to be docile enough to prevent any life-threatening side effects at least as far as we know."
The welcome clarification of this point in the comments section of the smart undergraduate girl's article (Michelle Gilson) pointed out that one NEEDS some compromise of the immune system for the retrovirus to live long enough to get into the cancer cells. That is why the chemotherapy has a function in the retrovirus cancer killing action. A healthy immune system usually kills the retrovirus too fast, which is why although most people have been exposed to it (the retrovirus), it does not by itself sit within us and automatically kill cancer in all of us. That was a point that I was wondering about myself, and I am glad Gilson clarified it.