Hepatitis B: The Sexually Transmitted Virus That Attacks the Liver

Hepatitis B virus (HBV) is a bloodborne and sexually transmitted infection causing acute and chronic liver disease.

Transmission Routes

• Sexual: Vaginal, anal, oral sex (highly efficient – 50–100x more infectious than HIV).
• Percutaneous: Needle sharing, needlesticks, tattoos, piercings, medical procedures.
• Perinatal: Mother-to-child at birth (major global route).
• Horizontal: Household contact (shared razors, toothbrushes) via micro-abrasions.

Clinical Course

• Acute HBV: Incubation 60–150 days. Symptoms: jaundice, fatigue, nausea, RUQ pain, dark urine. 95% of adults clear spontaneously → lifelong immunity.
• Chronic HBV: Persistence >6 months. Risk: 90% if infected at birth, 5–10% as adult. Can lead to cirrhosis, hepatocellular carcinoma (HCC).

Diagnosis

Marker	Interpretation
HBsAg	Current infection (acute or chronic)
Anti-HBc IgM	Acute infection
Anti-HBc IgG	Past or chronic infection
Anti-HBs	Immunity (vaccine or resolved infection)
HBeAg / Anti-HBe	High/low infectivity
HBV DNA	Viral load; guides treatment

Prevention & Treatment

• Vaccine: 3-dose series (0, 1, 6 mo). 95% effective. Universal birth dose + catch-up.
• Post-exposure prophylaxis: HBIG + vaccine within 24h (perinatal, needlestick, sexual assault).
• Antivirals (tenofovir, entecavir): Suppress replication, reduce cirrhosis/HCC risk. Not curative (cccDNA persists).
• Monitoring: ALT, HBV DNA, AFP, ultrasound q6mo for chronic infection.

Hepatitis B is vaccine-preventable. Screen high-risk groups; vaccinate all infants and at-risk adults.