Hepatitis B
A viral liver infection that can become chronic
Quick Facts
- Type: Viral liver infection
- Spread by: Blood and body fluids
- Prevention: Safe, effective vaccine
- Risk if chronic: Cirrhosis, liver cancer
Overview
Hepatitis B is an infection of the liver caused by the hepatitis B virus (HBV). It can range from a brief, mild illness to a serious, lifelong condition. When the infection clears within about six months, it is called acute hepatitis B; when it lasts longer, it becomes chronic hepatitis B, which can quietly damage the liver over many years.
Whether an infection becomes chronic depends largely on the age at which it is acquired. Infants and young children who are infected are much more likely to develop chronic infection, while most healthy adults clear the virus on their own. Chronic hepatitis B is a major cause of cirrhosis (liver scarring) and liver cancer worldwide. The good news is that hepatitis B is preventable with a safe, effective vaccine, and chronic infection can be managed with medication to protect the liver.
Symptoms
Many people with hepatitis B, especially children, have no symptoms. When symptoms occur, usually in acute infection, they may include:
- Fatigue and a general feeling of being unwell
- Yellowing of the skin and eyes (jaundice)
- Dark urine and pale stools
- Nausea, vomiting, and loss of appetite
- Abdominal pain, especially in the upper right area over the liver
- Joint pain and low-grade fever
Chronic hepatitis B often causes no symptoms for years, even while it damages the liver. This is why testing is important for people at risk, since the infection can progress silently until serious liver problems develop.
Causes
Hepatitis B is caused by the hepatitis B virus, which spreads when blood or certain body fluids from an infected person enter the body of someone who is not protected.
- Mother to baby: a major route worldwide, occurring during childbirth.
- Blood contact: sharing needles or other drug equipment, or accidental needlestick injuries.
- Sexual contact: through unprotected sex with an infected partner.
- Shared personal items: razors or toothbrushes that may carry traces of blood.
Hepatitis B is not spread through casual contact such as hugging, sharing food, coughing, or sneezing.
Risk Factors
Anyone unvaccinated can be infected, but some situations raise the risk.
- Being born to a mother with hepatitis B
- Injecting drugs or sharing needles
- Having unprotected sex or multiple partners
- Living with someone who has chronic hepatitis B
- Working in healthcare with exposure to blood
- Receiving long-term dialysis
- Coming from or living in a region where hepatitis B is common
Diagnosis
Hepatitis B is diagnosed with blood tests, which can also distinguish acute from chronic infection and show whether someone is protected.
- Blood tests for hepatitis B markers: detect the virus, the body's antibodies, and whether the infection is current, past, or resolved.
- Liver function tests: measure substances that indicate liver inflammation or damage.
- Viral load testing: measures the amount of virus in the blood to guide treatment.
- Liver imaging or elastography: ultrasound or specialized scans to assess liver scarring.
- Liver biopsy: occasionally used to evaluate the extent of liver damage.
People at higher risk should be screened even without symptoms, since early detection allows monitoring and treatment.
Treatment
Treatment depends on whether the infection is acute or chronic. Acute hepatitis B in adults usually clears on its own and needs only supportive care.
- Acute infection: rest, fluids, good nutrition, and avoiding alcohol while the body fights the virus; most adults recover fully.
- Chronic infection: antiviral medicines can suppress the virus, reduce liver inflammation, and lower the risk of cirrhosis and liver cancer; these are often taken long term.
- Regular monitoring: people with chronic hepatitis B need ongoing blood tests, liver assessments, and screening for liver cancer.
- Liver transplant: may be considered for advanced liver failure.
Not everyone with chronic hepatitis B needs medication immediately; a specialist decides based on viral load, liver health, and other factors.
Prevention
- Get the hepatitis B vaccine, which is safe, effective, and recommended for infants and at-risk adults
- Ensure newborns of infected mothers receive vaccine and protective treatment at birth
- Do not share needles, syringes, or drug equipment
- Use condoms to reduce sexual transmission
- Avoid sharing razors, toothbrushes, or other items that may carry blood
- Ensure tattoo and piercing equipment is sterile
When to See a Doctor
See a clinician if you have symptoms of liver problems such as jaundice, dark urine, or persistent fatigue, or if you may have been exposed to hepatitis B. Testing and, if needed, prompt preventive treatment after exposure are important. Seek urgent medical care for:
- Severe vomiting that prevents keeping fluids down
- Marked jaundice with confusion or extreme drowsiness
- Vomiting blood or black, tarry stools
- Significant abdominal swelling
These can signal severe liver problems that need immediate attention.
Frequently Asked Questions
Is there a vaccine for hepatitis B?
Yes. A safe and highly effective vaccine prevents hepatitis B and is recommended for all infants and for adults at higher risk. Vaccination is the best way to protect yourself and others from the virus.
Will acute hepatitis B become chronic?
It depends largely on age. Most healthy adults clear the infection within about six months, but infants and young children who are infected are much more likely to develop lifelong chronic hepatitis B.
How does hepatitis B spread?
It spreads through blood and certain body fluids, such as during childbirth, by sharing needles, through unprotected sex, or by sharing razors or toothbrushes. It does not spread through casual contact like hugging or sharing food.
Can chronic hepatitis B be cured?
Most chronic infections cannot yet be fully cured, but antiviral medicines can suppress the virus, protect the liver, and greatly reduce the risk of cirrhosis and liver cancer. Regular monitoring is an important part of care.
Is hepatitis B dangerous if I have no symptoms?
Yes, it can be. Chronic hepatitis B often causes no symptoms for years while quietly damaging the liver. This is why people at risk should be tested, so the infection can be monitored and treated before serious problems develop.
References
- Centers for Disease Control and Prevention (CDC). Hepatitis B.
- World Health Organization (WHO). Hepatitis B.
- Mayo Clinic. Hepatitis B — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. Hepatitis B.