Hepatitis B (HBV) is virus that infects the liver and most adults (95%) who are infected are able to quickly recover however some have long-lasting illness that can lead to liver disease, liver cancer and death. In babies and young children, HBV can also develop into a chronic infection leading to liver cirrhosis or liver cancer later in life. 350 million people worldwide are infected with HBV and it is the cause of 620,000 deaths each year.