In Australia, it has been estimated there were 222,599 people living with chronic hepatitis B (CHB) in 2020, representing 0.9% of the population. However, only 73% of people living with CHB in Australia are estimated to have been clinically diagnosed. In Australia, the most common routes of transmission for newly acquired infection are injecting drug use and sexual contact. The risk of chronic infection is greatest in those exposed to HBV early in life, while exposure in adulthood leads to self-limiting acute infection in most cases (>95 %). Nearly half (46%) of all people living with CHB in Australia were born in the Asia-Pacific region, with the most common countries of origin being China, Vietnam and Philippines.
Testing should be considered in all patients with elevated liver enzymes. Acute hepatitis B infection is defined as the presence of HBsAg and anti-HBc IgM in blood that persists for less than 6 months. Chronic hepatitis B infection is defined as persistence of infection (presence of HBsAg in blood) for longer than 6 months. Occult hepatitis B infection is defined as negative HBsAg and either positive or negative anti-HBc, with HBV DNA detectable in blood or liver tissue. Immunity through past infection is defined as positive anti-HBc and anti-HBs. All people being treated with antiviral therapy should undergo periodic review, including ALT, serum HBV DNA and, for tenofovir, renal function (eGFR) and serum phosphate.
