There are two different antigens that are produced by hepatitis B: the S antigen or Surface antigen and the E antigen. Anyone with S+ is considered a carrier. The E antigen is indicative of a high level of viral activity. There are some mutants/genotypes that are active sans E antigen, but they are not the norm. So someone who is E- and S+ is an "inactive carrier" (a somewhat deceptive term) but that individual tends to be FAR less susceptible to transmitting the disease. For example, some one who is E+ would likely have a viral load in the tens of million to billion range while some one who is E- and S+ would only have a viral load in the tens of thousands or less range. A viral load in the 10,000 range is not typically transmissible sexually and would likely require a transfusion/transplant to transmit. So perhaps that gives you a little idea of how this virus works.
It is my understanding that "exposure prone" means hacking some one open in such a way that the likely-hood of you (the doctor) getting cut is significantly increased. As I said before, blind suturing is a perfect example. I don't think that scopes would fall under this, but hospitals might take issue on an individual basis.
FYI, the genotype that is most prevalent in asia is extremely difficult to treat relative to what is found in North America and Western Europe.
