Hepatitis B is an infection caused by the hepatitis B virus, which is highly contagious and is spread through contaminated blood via needle sharing, blood transfusions, injections and unprotected sexual intercourse with an infected person. People can also be infected through unhygienic and unclean practices of tattooing, body piercing, acupuncture and at barbershops and nail salons. The virus can be passed from mother to baby.