To some extent, we all fear getting some type of infection. Lupus is an over-active immune system, immunosuppressants slow down that over activity and, thusly, makes a more prone to infection and/or catching something. So, we have to be very careful where we go, who we are around, and how we care for ourselves. So, your fear is a reasonable one and one in which you are not alone.
I do not take Cellcept, but there are many here who do. I hope that someone responds to you. I wish you the very best.
Peace and Blessings