A medication that is given as a “post-exposure†treatment to prevent hepatitis B. This means that HBIG is given after a person has been exposed to potentially infected blood or infected bodily fluids, which can include but is not limited to - contact with blood or through a needlestick, infants born to infected women, and through sexual contact or close household contact with an infected person. HBIG is often used as a post-liver transplant treatment.