Am I at risk of contracting mononucleosis by being around someone who has it if I am immunosuppressed, even though I have already had it?

If you have already had mononucleosis and are currently immunosuppressed due to medication, the chances of the virus reactivating are very low. The virus typically remains dormant in your body after you have been infected, and reactivation usually occurs in very rare cases in highly immunosuppressed individuals. It is unlikely that being around someone with mononucleosis would increase your risk of the virus reactivating.