Quick Answer
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
- Hepatitis B is caused by the hepatitis B virus (HBV), not by the same virus as hepatitis A or C.
- The virus is transmitted through blood, semen, and other body fluids, not through casual contact or food.
- Common routes include unprotected sex, sharing needles or syringes, and mother-to-child transmission during birth.
- Acute HBV infection may resolve on its own, especially in healthy adults; chronic infection is more common in infants.
- Chronic hepatitis B can lead to cirrhosis and liver cancer, especially without monitoring or treatment.
- Vaccination is the most effective way to prevent hepatitis B infection.
Context Most Pages Skip
Many people hear "hepatitis" and lump all forms together, but each type has a different cause and spread. Hepatitis B specifically is a viral infection that can quietly damage the liver for years before symptoms appear. Understanding how HBV enters the body and why some people clear it while others do not is key to prevention. Unlike hepatitis A, which spreads through contaminated food or water, or hepatitis C, which is mainly transmitted via blood, hepatitis B has its own distinct patterns. Recognizing these differences helps you take the right steps to protect yourself and others.
Frequently Asked Questions
What are the causes of hepatitis b?
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
What causes hepatitis?
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
What causes hepatitis c?
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
What are the causes of hepatitis?
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
What causes hepatitis a?
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
What causes autoimmune hepatitis?
Hepatitis B is caused by the hepatitis B virus (HBV), which attacks the liver. The virus spreads through contact with infected blood, semen, or other body fluids—most often during unprotected sex, shared needles, or from mother to baby at birth. Many adults clear the virus naturally, but infants and young children are more likely to develop a chronic infection that can lead to serious liver damage, cirrhosis, or liver cancer. A safe and effective vaccine provides strong protection.
Related Questions
Sources & Further Reading
- CDC — Sexually Transmitted Infections
- CDC STI Treatment Guidelines
- WHO — Sexually transmitted infections fact sheet
- MedlinePlus — Sexually Transmitted Diseases
Figures reflect CDC surveillance and WHO estimates; they are population statistics, not personal risk predictions.