A look into…Hepatitis B

Infection with the hepatitis B virus (HBV) is a major problem throughout the world. Over 240 million people are estimated to be HBV surface antigen(sAg)-positive, with up to 25% of individuals with chronic HBV infection dying from cirrhosis or hepatocellular carcinoma (HCC).

HBV is transmitted via blood (in medical, occupational or other setting) and sexual contact. The Epiomic™ database subdivides the diagnosed patient population by transmission route. Disease transmission has been dramatically decreased in countries with vaccination programmes, and the HBV vaccine is considered safe and effective.

HBV is a DNA virus that replicates via reverse transcription of an RNA intermediate. The virus forms the characteristic covalently closed circular DNA (cccDNA) which determines the chronicity of infection and carcinogenesis. HBV can also integrate into the host cell DNA, which further favours chronicity. HBV-infected cells produce large amounts of subviral particles (SVP) that are not infectious, but their immunogenic properties allow the virus to neutralize anti-HBV antibodies and cause “exhaustion” of HBV-specific T-cells, leading to selective immune dysfunction.

HBV can cause both acute and chronic infections. Hepatitis B and the subsequent liver damage are a consequence of the host immune response. As chronic HBV (cHBV) infection is usually asymptomatic until cirrhosis or HCC develop, screening programmes in populations at increased risk are recommended. The infection is detected using serological assays and nucleic acid tests. The Epiomic™ database contains a forecast of the population most likely to have been diagnosed with HBV and those who are co-infected with HIV.

Current treatments: peginterferon alpha (pegIFN) and nucleoside analogues (NAs), suppress HBV replication and reduce the risk of developing cirrhosis and HCC. However, they usually do not eradicate the virus as cccDNA persists in infected cells. NAs are recommended for life-long treatment. The Epiomic™ database is invaluable in sizing up this population and contains a forecast of the estimated population currently undergoing treatment.

Quick Fact

Patients with cHBV are at high risk of developing liver cirrhosis and hepatocellular carcinoma.