From the Guidelines
Hepatitis B surface antigen (HBsAg) is a definitive marker of active hepatitis B infection, and its presence in the blood indicates that the person is infected and can potentially spread the virus to others. The detection of HBsAg in a blood test is a critical component of standard hepatitis B screening, which is often included in prenatal testing, blood donation screening, and evaluation of liver disease [ 1 ]. When HBsAg is positive for more than 6 months, it indicates chronic hepatitis B infection, which may require treatment with antiviral medications such as entecavir, tenofovir, or lamivudine to suppress viral replication and prevent liver damage [ 1 ].
Key Considerations
- The goals of antiviral treatment are to achieve sustained suppression of HBV replication and remission of liver disease to prevent cirrhosis, hepatic failure, and hepatocellular carcinoma [ 1 ].
- Approved first-line treatments are pegylated interferon-α2a, entecavir, and tenofovir, and the choice of antiviral drug depends on patient characteristics, HBV DNA and serum aminotransferase levels, and HBeAg status [ 1 ].
- Individuals who test positive for HBsAg should be monitored regularly for liver function and viral load, as chronic hepatitis B can lead to serious complications including cirrhosis and liver cancer [ 1 ].
- Close contacts of infected individuals should be vaccinated against hepatitis B if they haven't been previously immunized [ 1 ].
Management and Treatment
- The treatment of chronic hepatitis B infection should be guided by the most recent and highest quality evidence, which recommends the use of antiviral medications such as entecavir, tenofovir, or lamivudine to suppress viral replication and prevent liver damage [ 1 ].
- The management of hepatitis B infection should also include regular monitoring of liver function and viral load, as well as vaccination of close contacts against hepatitis B [ 1 ].
From the Research
Hepatitis B Surface Antigen Reduction
- The reduction of hepatitis B surface antigen (HBsAg) levels is a key goal in the treatment of chronic hepatitis B virus (HBV) infection 2, 3, 4, 5, 6.
- Studies have shown that antiviral therapies such as entecavir and tenofovir can reduce HBsAg levels in patients with chronic HBV infection 3, 4, 5, 6.
- A study comparing the effects of tenofovir alafenamide and entecavir on HBsAg levels found that tenofovir alafenamide significantly decreased HBsAg levels compared to entecavir 3.
- Another study found that switching from long-term entecavir administration to tenofovir could contribute to the reduction of HBsAg levels in a specific subpopulation of patients 6.
Comparison of Antiviral Therapies
- A systematic review and Bayesian meta-analyses found that tenofovir and entecavir are the most effective antiviral agents for chronic hepatitis B, with tenofovir being the most effective in inducing undetectable levels of HBV DNA and improving liver histology 4.
- A study comparing the effects of combination therapy of entecavir or tenofovir with pegylated interferon-α found that some studies have shown promising results, but there is no robust evidence that combination therapy is superior to monotherapy 2.
Predictive Factors for HBsAg Reduction
- A study found that age, HBV DNA, and alanine aminotransferase (ALT) levels were significantly correlated with HBsAg levels at baseline, but the correlation was reduced by entecavir treatment and lost after 2 years of treatment 5.
- The same study found that early decline of HBsAg levels at 12/24 weeks was not associated with HBV DNA suppression or HBeAg seroconversion 5.