Hi
Are you saying that you had Mono when you were a child already? If so then you should be ok; however, with EBV or any virus, it can be reactivated at any time. Once we get a virus, it never truly goes away, it just usually lies dormant in our bodies. It could be easier for an immunocompromised person for it to reactivate, I'm not sure.
Now, in saying that...Mono is passed from bodily fluids. This is why it is nicknamed "the kissing disease"
So I would be careful in that aspect, as well as drinking from the same container, eating from the same utensil, etc.
The same applies if you have never had Mono, except you should be extra careful until your friend is in the clear (usually around 3 months).
Hope this helps and good luck to you!
Edit: I should add...having EBV is not the same as having Mono, EBV is one of the viruses that can cause Mono, but it can also cause symptoms of Chronic Fatigue Syndrome, which in itself is not contagious.
Hope I haven't confused you! :lol: