Rhod, you haven’t said what his dosage is. At one point, long ago, I was on 100mg of prednisone and 200mg of Imuran, another immunosuppressant. I made sure I got a flu shot every year. I washed my hands frequently with antibiotic soap. I took a multivitamin daily, Centrum for Men. I did not get sick very often and I did NOT isolate myself from everyone. The immune system is suppressed, but not eliminated. Maybe I was lucky, who knows? I did have side effects from the prednisone, but I didn’t get sick much. Jim