Overview
Serious liver infection caused by the hepatitis B virus (HBV). Leading cause of liver cirrhosis and hepatocellular carcinoma worldwide. Highly effective vaccine available.
Symptoms
Symptoms | Frequency | Severity | Onset |
|---|---|---|---|
| Fatigue | 70% | Mild | Early |
| Loss of appetite | 60% | Mild | Early |
| Malaise | 65% | Mild | Early |
| Nausea | 55% | Mild | Early |
| Arthralgia | 25% | Mild | Early |
| Fever | 30% | Mild | Early |
| Myalgia | 30% | Mild | Early |
| Vomiting | 35% | Mild | Early |
| Diarrhea | 15% | Mild | Early |
| Headache | 25% | Mild | Early |
| Joint swelling | 10% | Mild | Early |
| Rash | 15% | Mild | Early |
| Swollen lymph nodes | 10% | Mild | Early |
| Abdominal pain | 50% | Moderate | Peak |
| Dark urine | 45% | Moderate | Peak |
| Hepatomegaly | 50% | Mild | Peak |
| Jaundice | 40% | Moderate | Peak |
| Itching | 20% | Mild | Peak |
| Splenomegaly | 15% | Mild | Peak |
| Weight loss | 15% | Mild | Any phase |
Transmission
Overview
Serious liver infection caused by the hepatitis B virus.
Overview
Hepatitis B virus (HBV) is a partially double-stranded DNA virus transmitted via blood, sexual contact, and perinatally. Globally, ~296 million people live with chronic HBV infection. Most acute infections in adults resolve spontaneously; chronic infection develops in ~95% of infected newborns and ~5% of infected adults.
Emergency Signs
Seek urgent medical care if:
-
Rapidly deepening jaundice (yellowing of skin/eyes) over hours to days
-
Severe abdominal pain, especially right upper quadrant
-
Altered mental status, confusion, or extreme drowsiness (hepatic encephalopathy)
-
Vomiting blood or passing black tarry stools (variceal bleeding — cirrhosis complication)
-
Sudden abdominal distension (ascites)
Detailed Symptoms
Most common signs and symptoms
Acute hepatitis B (incubation 1–6 months):
-
Jaundice (yellowing of skin and eyes), dark urine, pale stools
-
Fatigue, anorexia, nausea, vomiting, abdominal pain
-
Arthralgia and urticaria (serum sickness-like prodrome in ~10%)
-
Fever (usually low-grade or absent)
-
~70% of acute infections are subclinical or anicteric
Chronic hepatitis B (after 6 months):
-
Often asymptomatic for years or decades
-
Fatigue, abdominal discomfort
-
Signs of advanced disease: jaundice, ascites, spider angiomata, splenomegaly (cirrhosis)
Knowing the symptoms is the first step to a quick response.
Course of Disease
Typical disease course:
- Incubation period: 45–180 days (average 60–90 days).
- Acute phase:
- Prodrome (1–2 weeks): fatigue, anorexia, nausea, right upper quadrant discomfort, arthralgias.
- Icteric phase: jaundice in ~30% of adults (rarely in children). Dark urine, pale stools. ALT peaks 1,000–3,000 IU/L. Duration: 1–3 months.
- Anicteric infection: ~70% of adults, often undiagnosed.
- Resolution or chronicity:
- Adults: HBsAg clearance within 6 months in >95%. Anti-HBs seroconversion indicates recovery.
- Chronicity: persistent HBsAg >6 months. Phases: immune tolerant → immune active → inactive carrier → reactivation (variable progression).
- Chronic phases: HBeAg-positive chronic hepatitis → HBeAg seroconversion → HBeAg-negative chronic hepatitis → inactive carrier state.
Serological timeline: HBsAg appears 1–10 weeks after exposure, before symptoms. Anti-HBc IgM marks acute infection. Anti-HBs indicates recovery and immunity.
Diagnosis
How this disease is identified
Key serological markers:
-
HBsAg: positive = active HBV infection (acute or chronic)
-
Anti-HBs: positive = immunity (vaccination or resolved infection)
-
HBeAg: marker of high replication and infectivity
-
Anti-HBc IgM: acute infection or reactivation
-
Anti-HBc IgG: prior or current infection
-
HBV DNA (viral load): quantifies replication; guides treatment decisions
-
Liver function tests: elevated ALT/AST in active disease
-
Liver biopsy or FibroScan: assesses fibrosis stage in chronic disease
-
Screen for HDV coinfection in endemic areas
Treatment
Available treatment methods
Acute hepatitis B: supportive care
- antivirals not routinely recommended unless severe/fulminant.
Chronic hepatitis B:
-
Tenofovir disoproxil fumarate (TDF) or Tenofovir alafenamide (TAF): first-line oral antivirals
-
excellent safety profile
-
Entecavir: alternative first-line option
-
Pegylated interferon-alfa (Peg-IFN): finite treatment (48 weeks)
-
suitable for select patients
-
achieves HBsAg loss in ~3–7% Goals of treatment: suppress viral replication, prevent fibrosis progression, reduce HCC risk. Treatment is lifelong for most patients. Regular monitoring: HBV DNA, liver enzymes, AFP, and HCC surveillance by ultrasound every 6 months.
Most cases are effectively treated with early diagnosis.
Prevention Details
How to protect yourself
The hepatitis B vaccine is one of the most effective vaccines available (95%+ efficacy):
-
Standard schedule: 3-dose series (0, 1, 6 months) or 4-dose accelerated series (0, 1, 2, 12 months)
-
Infants: birth dose + completion of 3-dose series by 6 months — prevents perinatal transmission
-
Post-exposure prophylaxis: HBV vaccine + HBIG (hepatitis B immunoglobulin) within 24 hours of exposure Additional prevention:
-
Use barrier contraception (condoms)
-
Never share needles, syringes, or personal items (razors, toothbrushes)
-
Ensure blood and blood products are screened
-
Universal precautions in healthcare settings
Preparation is the best protection.
Travel Advice
-
Vaccination is recommended for all unvaccinated travelers regardless of destination.
-
Higher risk in sub-Saharan Africa, Asia, Eastern Europe, and Central America.
-
Travelers requiring medical procedures or blood transfusions abroad are at particular risk.
-
Avoid unprotected sex, sharing needles, or unsterile tattooing/piercing.
-
Carry hepatitis B vaccination record; some countries require proof for long-term visas (healthcare workers).
-
Travelers injured abroad should receive post-exposure prophylaxis (vaccine ± HBIG) upon return.
How common is it?
Statistics and geographic data
WHO estimates ~296 million people have chronic HBV infection globally (2019). Approximately 820,000 deaths per year from HBV-related cirrhosis and HCC. Prevalence is highest in sub-Saharan Africa and East Asia (5–10%). Intermediate in South Asia, Middle East, Eastern Europe, and Central Asia (2–5%). Low in Western Europe, North America, Australia (<2%). Perinatal transmission is the dominant route in East Asia; blood-borne and sexual transmission predominate in low-prevalence regions.
Risk Factors
Who is most at risk
Risk factors for acquiring hepatitis B:
-
Birth to an HBsAg-positive mother: The most important risk factor globally. Perinatal transmission leads to chronic infection in ~90% of cases. Without prophylaxis, 70–90% of infants born to HBeAg-positive mothers become infected.
-
Unvaccinated status: Lack of vaccination is the primary modifiable risk factor. HBV vaccine is >95% effective at preventing infection.
-
Healthcare workers and first responders: Occupational needlestick injuries carry a 6–30% HBV transmission risk from a single exposure to HBeAg-positive blood (compared to 0.3% for HIV).
-
People who inject drugs (PWID): Sharing of needles, syringes, and drug preparation equipment. Prevalence of HBV markers reaches 40–60% in some PWID populations.
-
Sexual transmission: Multiple sexual partners, men who have sex with men (MSM), and sexual contact with HBV-infected individuals. HBV is 50–100 times more infectious than HIV via sexual contact.
-
Household contacts of chronically infected individuals: Sharing razors, toothbrushes, or contact with open wounds.
-
Residence in or travel to endemic areas: Sub-Saharan Africa (6–8% prevalence), East Asia (5–7%), Southeast Asia (2–5%).
-
Recipients of blood products or organ transplants in countries without universal screening.
-
Hemodialysis patients: Impaired immune response leads to lower vaccine efficacy (60–70%) and higher infection risk.
Risk factors for progression to chronic infection:
-
Age at infection: 90% chronicity in neonates; 30% in children aged 1–5; <5% in immunocompetent adults.
-
Immunosuppression: HIV co-infection, chemotherapy, organ transplant recipients.
-
Male sex: Males are more likely to remain chronically infected and develop HCC.
Complications Details
Potential complications
Acute complications:
-
Fulminant hepatic failure: rare (<1%) but high mortality
-
requires liver transplant evaluation
Chronic infection complications:
-
Liver cirrhosis: develops in ~20–30% of chronically infected over 20–30 years
-
risk of liver failure
-
Hepatocellular carcinoma (HCC): HBV is the leading cause of HCC globally
-
risk increased 20–100-fold compared to uninfected
-
regular surveillance required
-
Extrahepatic manifestations: polyarteritis nodosa, glomerulonephritis, cryoglobulinemia
-
HDV coinfection/superinfection: accelerates fibrosis
-
higher risk of cirrhosis and HCC
Recovery & Outlook
Expected outcomes and recovery
Acute infection prognosis: >95% of immunocompetent adults clear the virus spontaneously. Fulminant hepatitis occurs in <1% of cases but carries 60–80% mortality without transplant.
Chronic infection prognosis:
-
Risk of chronicity inversely correlates with age at infection: 90% in neonates, 30% in children 1–5 years, <5% in adults.
-
Of chronic carriers: 15–40% develop cirrhosis, hepatocellular carcinoma (HCC), or liver failure over decades.
-
HCC risk: 100× higher than uninfected population. Annual HCC incidence in cirrhotics: 2–5%.
-
With antiviral treatment (tenofovir, entecavir): viral suppression in >95%, regression of fibrosis possible, HCC risk significantly reduced but not eliminated.
Functional cure (HBsAg loss): Achieved in <10% with current therapy. HBV DNA persists as cccDNA in hepatocytes indefinitely.
