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Epidemiology of Hepatitis B infection
- 2 million people have evidence of past or present infection with hepatitis B virus (HBV), and 248 million individuals are chronic carriers
- Prevalence of chronic infection ranges from <2% in low-prevalence areas (U.S) to 2-7% in Asia
- The rate of progression from acute to chronic HBV infection
- 90 percent for perinatally acquired infection
- 20 to 50 percent for infections between the age of one and five years
- <5 percent for adult-acquired infection
- High risk for HCC; can develop without cirrhosis
Posted 01/10/17 10:34:37 AM by Ying Liu
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Phases of Hepatitis B Infection
- Acute Infection marked by appearance of HBsAg 1-10 weeks after acute exposure. Clears after 4-6 months and Surface Ab develops
- Persistence of HBsAg for 6 months implies chronic infection.
- 5% of immunocompetent adult patients progress to chronic infection
- Multiple Phases of Chronic infection exist
- Replicative Phase: Immune Tolerance (HBeAg and HBV DNA but normal LFTs)
- Replicative Phase: Immune Clearance (HBeAgseroconversion with increases in LFTs), characterized by flares
- Inactive Carrier State: HBeAgneg, Anti-HBepos, and HBV DNA neg
- HBeAgneg Chronic Hepatitis: Low levels HBV DNA, HBeAgneg
- Reactivation can occur after clearance, particularly in the setting of immunosuppression
- Can have co-infection with Hepatitis C and D (needs HBV Surface Ag to invade cells)
Posted 01/10/17 10:35:45 AM by Ying Liu
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Management of Chronic Hepatitis B infection
- Treatment is depends on presence of cirrhosis, ALT level and HBV DNA level as well as age/comorbidities as it is essentially lifelong treatment
- Since HBV DNA integrates into host DNA, there is currently no cure
- Options for treatment include:
- Tenofovir (1st-line)
- Entecavir (good for CKD)
- Lamivudine (some resistance)
- Pegyatedinterferon (most cost-effective)
- Adefovir (some role in lamivudine resistant disease)
- HCC screening is important given increased risk
- No data for treatment of acute HepB given high rates of clearance for adults
Posted 01/10/17 10:39:52 AM by Ying Liu
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- 715 patients with HBeAg positive chronic HBV
- Randomized to 0.5mg entecavir or 100mg lamivudine once daily
- Histologic improvement after 48 weeks occurred in significantly more patients in entecavir group
- Mean reduction in serum HBV DNA also greater in entevabir group (p<0.001).
- No difference in HBeAg seroconversion rates
Posted 01/10/17 10:41:22 AM by Ying Liu
Created by Christopher Kelly
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It is not meant to replace the advice of a health professional.