A 27-year-old physician exposed to Hepatitis B–positive blood is vaccinated with adequate anti-HBs titers. What is the most appropriate management to prevent infection?

• A. No treatment necessary
• B. HBsAg and HBsAb testing; HBV vaccination if needed
• C. HBIG and HepB vaccine
• D. Post-exposure antiviral therapy only

Answer: (A)

When someone has completed hepatitis B vaccination and shows a protective anti-HBs titer, no post-exposure prophylaxis is needed after exposure to HBV-positive blood. A protective anti-HBs level (≥10 mIU/mL) means circulating antibodies can neutralize the virus and immune memory can rapidly respond, preventing infection. In this scenario, the physician’s adequate anti-HBs titers provide full immunity, so the appropriate action is no treatment.

If immunity were unknown or inadequate (anti-HBs <10 mIU/mL or no vaccination), post-exposure prophylaxis with hepatitis B immune globulin plus vaccination would be considered. Antiviral therapy is not used as post-exposure prophylaxis for HBV.