After infection an individual will have an acute phase of hepatitis, with or without symptoms. Thereafter the individual’s own immune response will clear most of the HBV infections.
In about 5% of infected adults, their immune systems are unable to clear the HBV, which results in ongoing virus replication in the liver.
Persistent infection is more common in individuals infected at an early age; 90% of children infected at birth and about a third of young children under age five years will not clear the infection. Individuals with a defective immune system, like HIV infected persons, are also more prone to ongoing disease.
If viral replication persists beyond six months, it is referred to as "chronic" HBV infection. These individuals are considered "carriers" of HBV.
HBV infection is the most common chronic viral infection in the world, with over 350 million HBV carriers worldwide. Hepatitis B infections cause more than half a million deaths annually.
HBV infection is common in South Africa.
Chronic HBV infection occurs more frequently in rural black males (up to 16%) and females (up to 12%). In these populations, HBV infection is acquired very early in life, mainly as a result of close person-to-person transmission among children before the age of 5 years. An increase is also seen at the age when people become sexually active. Chronic HBV infection is also up to 5 times more prevalent in HIV-positive populations
Chronic HBV infection is less than 1% in the other population groups in South Africa, with the exception of the very small Chinese community (4%).
South Africa has had one of the highest rates of liver cancer in the world, and this is linked to the high rate of hepatitis B.
Since the introduction of hepatitis B vaccinations of all children in 1995, it is hoped that the disease and its complications will soon become far less prevalent.
Revised and reviewed by Dr Karin Richter, MMed Path (Medical Virology), FC Path(SA) Viro, Dip HIV Man (SA), Dip Obst (SA), MBChB , Clinical Virologist, Senior Lecturer, Department of Medical Virology, University of Pretoria, Faculty of Health Sciences, and Consultant Pathologist, Tshwane Academic Division, National Health Laboratory Services (NHLS) February 2015.
Previously reviewed by Dr Eftyhia Vardas BSc (Hons), MBBCh, DTM&H, DPH, FC Path (Virol), MMed (Virol), Clinical Virologist, Director HIV AIDS Vaccine Division, Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, University of the Witwatersrand.