Hepatitis B — Serology and Markers

A 28-year-old healthcare worker in Delhi undergoes post-exposure prophylaxis (PEP) after a needlestick injury from an HBV-positive patient. At 6 weeks post-exposure, serology shows: HBsAg (−), anti-HBs (+), anti-HBc (−). Which serological pattern best distinguishes successful vaccination response from resolved natural HBV infection?

A 32-year-old male from Mumbai presents with jaundice, malaise, and dark urine for 2 weeks. He reports a history of needle-stick injury 6 months ago while working as a healthcare worker. Physical examination reveals hepatomegaly and icterus. Laboratory investigations show: ALT 1200 IU/L, AST 950 IU/L, total bilirubin 8.2 mg/dL, and albumin 3.8 g/dL. Serological tests reveal: HBsAg positive, anti-HBc IgM positive, anti-HBc IgG negative, HBeAg positive, anti-HBe negative. What is the most likely interpretation of these findings?

A 35-year-old man from Delhi presents with jaundice and elevated transaminases. Serology shows HBsAg+, anti-HBc+, HBeAg+, and HBV DNA >10^5 copies/mL. He has compensated cirrhosis on ultrasound. What is the drug of choice for initiating antiviral therapy?

A 42-year-old woman from Mumbai with chronic hepatitis B (HBsAg+, anti-HBc+, HBeAg−, anti-HBe+, HBV DNA 2×10^4 copies/mL) and normal liver histology on biopsy is found to have lamivudine-resistant HBV (YMDD mutation). What is the drug of choice for salvage therapy?

A 45-year-old woman from Mumbai is found to be HBsAg positive on routine blood donation screening. She is asymptomatic with normal liver function tests (ALT 32 IU/L). Serology shows: HBsAg positive, anti-HBc IgG positive, anti-HBc IgM negative, HBeAg negative, anti-HBe positive, HBV DNA 1.2 × 10⁶ copies/mL. What is the most appropriate next step in management?