questions of a layman - couldn't they initially do a small infusion of the [may be even weakened version of that] viruses to check for the immune reaction? May be such infusion would really serve as a vaccine prepping the immune system for the main infusion later? - though immune system killing the viruses may be nullifying the treatment - then may be when doing such therapy the patient needs to be [somewhat] immunosuppressed similar to transplant situations?