212.2 📚 國考版

212.2.0.1 必背 — HAV Features

  • ssRNA picornavirus
  • Fecal-oral transmission
  • Never chronic (key distinguishing feature)
  • Acute hepatitis with high AST/ALT (1000+)
  • IgM positive = acute
  • IgG = past/vaccine immunity

212.2.0.2 必背 — Risk Groups

  • Homeless (2017-2024 USA outbreaks)
  • MSM, IDU
  • International travelers to endemic regions
  • Chronic liver disease (severe if infected)
  • Older adults (higher fulminant risk)

212.2.0.3 必背 — Severity

  • 0.3% overall mortality
  • 2-3% in ≥ 50 yr
  • 1-2% fulminant in adults
  • Chronic liver disease: severe disease risk

212.2.0.4 必背 — Vaccine

  • 2-dose inactivated (HAVRIX, VAQTA) 6-12 mo apart

  • 95% efficacy

  • Universal childhood 12-23 mo
  • Outbreak vaccination

212.2.0.5 必背 — Post-Exposure Prophylaxis

  • Vaccine + IG within 14 days
  • IG for high-risk (< 12 mo, > 40 yr, immunocompromise, chronic liver disease)

212.2.0.6 必背 — Diagnosis

  • IgM anti-HAV acute
  • Highly elevated AST/ALT (1000+)
  • Prolonged INR = severe

212.2.0.7 必背 — 2017-2024 USA Outbreaks

  • Homeless + IDU + MSM
  • CA, KY, TN, MI, FL clusters
  • Mass vaccination response