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- HBV: dsDNA hepadnavirus, NTCP receptor, cccDNA persistence, integration â HCC
- Transmission: vertical (endemic) > sexual + blood
- Chronic risk: perinatal 90%, adult 5-10%
- Phases: immune tolerant â immune active (HBeAg+) â inactive carrier â reactivation
- Markers: HBsAg (current), anti-HBs (immune), HBeAg/anti-HBe, anti-HBc IgM (acute)/IgG (past/chronic), HBV DNA (load)
- First-line Tx: TAF, TDF, Entecavir; lifelong typically
- Reactivation prophylaxis: anti-CD20 (rituximab), high-dose steroids, chemo, anti-TNF, transplant
- Vertical prevention: TDF 3rd trimester + birth vaccine + HBIG = < 5% transmission
- HCC surveillance: cirrhotic + high-risk Asian/African with US + AFP q6 mo
- Vaccine: 3-dose recombinant, > 95% efficacy, universal + birth dose
- HBV cure (2024-2025): bulevirtide, GalNAc-siRNA, capsid modulators, therapeutic vaccines
- Atezolizumab + bevacizumab = advanced HCC first-line (IMbrave150)
- Taiwan success: 1984 vaccine program reduced HBsAg+ from 15-20% to < 1% in vaccinated cohorts