Viral

Hepatitis B

Efficiently transmitted through blood, semen and vaginal fluid — and a highly effective vaccine prevents it.

What's at stake: Serious

Often clears on its own, but chronic infection can cause cirrhosis and liver cancer. Vaccine-preventable.

Cause

Virus (HBV)

Asymptomatic

Often, especially acute phase

Curable

No, most adults clear it naturally

Vaccine

Yes, highly effective 3-dose series

Overview

Hepatitis B virus (HBV) infects the liver and spreads through blood, semen, and vaginal fluids. It is generally regarded as far more infectious than HIV per exposure, although no study has measured a per-act probability for sex, which is why this app shows no number for it. Most adults who are infected clear the virus naturally within 6 months (acute infection); about 5 to 10% develop chronic infection, which can lead to cirrhosis and liver cancer over decades. A safe, effective vaccine has been available since the 1980s and is part of childhood schedules in most countries.

How it spreads

Unprotected vaginal or anal sex
Sharing needles, syringes, or drug equipment
Blood-to-blood contact (transfusions, medical procedures)
Mother to newborn during birth
Sharing personal items with blood exposure (razors, toothbrushes)

Symptoms

Fatigue and weakness
Jaundice (yellowing of skin or eyes)
Nausea, vomiting, abdominal pain
Dark urine, pale stools
Joint pain

Acute hepatitis B is asymptomatic in many adults; up to 50% have no symptoms. Chronic infection is often asymptomatic for years, leading to silent liver damage. Diagnosis is via blood test (HBsAg, anti-HBc).

Vaccine

The hepatitis B vaccine is highly effective (>90% protection after a full 3-dose series) and provides lifelong immunity in most people. It is included in childhood vaccination schedules in most countries. Adults who were not vaccinated as children can still be vaccinated; check with your GP. Post-exposure prophylaxis (HBV immunoglobulin + vaccine) can prevent infection after a known exposure.

Treatment

Acute HBV usually resolves on its own. Chronic HBV is not curable but is managed with antivirals (tenofovir, entecavir) that suppress viral replication and reduce liver disease progression. Lifelong monitoring is required.

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Educational purposes only. Consult a healthcare provider for personal medical advice.