Hepatitis B Virus (HBV) Infection
- Posted by Lele M
- On 21/02/2018
- Hepatitis B
HBV infection is one of the most prevalent serious chronic diseases in the world today, with over 300 million infected individuals. It leads to a spectrum of liver disease, ranging from acute through to chronic hepatitis, cirrhosis and primary liver cancer or hepatocellular cancer (HCC). As a result of Hepatitis B infection, HCC is the most common cancer encountered world-wide today.
Acute HBV infection can be either asymptomatic or present with symptomatic acute hepatitis.
Transmission of HBV
HBV is transmitted when the blood or body fluid of an infected person enters the body of a person who is not infected.
The most common mode of spread in the world today is by vertical transmission, which is infection from mother to baby at the time of childbirth. This has been a particular problem in Asian, African and Polynesian ethnic groups over the years. It can be prevented by vaccination of all babies soon after birth. A universal, free vaccination program was introduced in New Zealand in 1987, which will ultimately see the numbers of infected individuals in the country reduce.
Most adults infected with the virus recover over a period of months, but 5%–10% are unable to clear the virus and become chronically infected. This can be detected in the blood by the ongoing presence of HBsAg or hepatitis B surface antigen.
Many chronically infected persons have mild liver disease with little or no long-term consequences. Other individuals with chronic HBV infection develop active disease (chronic active hepatitis), which can progress to cirrhosis and liver cancer. However, as carriers of the virus all infected individuals remain a risk for spreading the virus to others through blood contamination and sexual contact. All HBsAg carriers require life-long monitoring, and if active disease is present therapeutic intervention is warranted.
There is currently no treatment option for cure of chronic infection but we do have medications, which if taken life-long can control viral replication and disease activity in the liver, and reduce the chances of development of liver failure and liver cancer. The development of resistance to these medications is an ongoing problem.
One of the principal challenges with HBV disease relates to our inability to predict outcome and progression of HBV infection. There is an urgent need to develop new medications which can clear the virus from the liver and eliminate the risk of serious liver damage or formation of liver cancer.
It is currently estimated there are at least 100,000 individuals in New Zealand with chronic HBV disease, mostly over the age of 35. For many of these individuals the development of curative treatments for HBV disease is critical if they are to be prevented from developing liver failure (requiring liver transplant) or liver cancer.
Update July 2022:
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Written by Mr Richard Stubbs, MD FRCS FRACS
Managing Director and Investigator
P3 Research Wellington Unit