Hepatitis B is caused by the hepatitis B virus (HBV). It spreads through infected blood and body fluids. The virus attacks liver cells and can cause both short-term (acute) and long-term (chronic) liver disease. Hepatitis B spreads more easily than HIV and can survive outside the body for up to a week.
How Hepatitis B Spreads
Unlike hepatitis A, you cannot get hepatitis B from food or water. The virus spreads in different ways depending on where you live and your daily activities.
1. Mother-to-Child Transmission
A common cause of hepatitis B is when a mother passes the virus to her baby during birth. This happens most in parts of Africa, Asia, and the Pacific Islands. Without treatment, most babies infected this way will have chronic hepatitis B. This can lead to liver problems later in life. Babies need a hepatitis B vaccine and special medicine (HBIG) within 12 hours of birth to stay healthy.
2. Childhood Contact
In some countries, young children can get hepatitis B through close contact at home. This can happen when they share things like toothbrushes or come into contact with wounds. Many children with hepatitis B do not feel sick, so the infection may go unnoticed for years.
3. Unprotected Sex
Hepatitis B can spread through sex without a condom. It spreads through semen, vaginal fluids, and blood. People at higher risk include:
- Those with many sexual partners
- Men who have sex with men (MSM)
- People with other sexually transmitted infections (STIs)
- Sex workers and their clients
Condom use and vaccination help prevent this.
4. Sharing Needles
Sharing needles is a major cause of hepatitis B, especially among people who inject drugs. Using clean needles through needle exchange programmes reduces this risk.
5. Workplace Exposure
Some workers face extra risk of hepatitis B. This includes healthcare workers and emergency responders who may be exposed to blood through injuries. Vaccination and protective gear lower this risk but accidents can still happen.
Other Ways to Catch Hepatitis B
Unsafe Medical Care
In some countries, poor sterilisation during medical or dental procedures can spread hepatitis B. This used to be common through blood transfusions, but is now rare in countries with safe healthcare systems.
Sharing Personal Items
You can catch hepatitis B by sharing:
- Razors
- Toothbrushes
- Nail clippers
- Tattoo or piercing tools
Even tiny drops of blood on these items can cause infection.
Unsafe Tattoos and Piercings
Getting tattoos or piercings in unclean settings increases your risk. This is common in prisons or unlicensed studios. Clean, professional parlours are usually safe.
Contact Sports and Accidents
Rarely, hepatitis B spreads through sports like boxing or rugby when people are exposed to blood. Using gloves and disinfectants during first aid lowers this risk.
Higher Risk Groups
Some people are more likely to catch hepatitis B:
- People with HIV or cancer treatment
- Residents in care homes or mental health hospitals
- People in prison
Their weaker immune systems make it harder to fight off the virus.
Who Is at Higher Risk of Hepatitis B?
Groups with the highest risk include:
- Babies born to infected mothers
- People who inject drugs
- Those with many sexual partners
- Men who have sex with men
- Healthcare and emergency workers
- People living with someone who has hepatitis B
- People in prison
- Travellers to countries where hepatitis B is common
Summary of Hepatitis B Causes
Hepatitis B spreads through contact with infected blood or body fluids. Common causes include birth, sex, needle sharing, and unsafe medical care. With vaccines, safer habits, and good healthcare, hepatitis B is preventable—even in high-risk areas
