Many People use the Power Items to EV train in 2 stats at the same time, I have heard from some that Pokerus effects the Power Items, I've heard from some it doesn't, I haven't been able to do a good test to see yet, my plan is to get a Pokemon, see what it is at level 100 as far as it's stat, infect it with Pokerus, use a Power Item on it, and see if the stat goes up 2 points... that's all I can see to see if it really works like that.