Distinctive Features in Chinese Children

General

• 350 million people world-wide are carriers and 25-40% of them at risk of developing liver failure and liver cancer.
• Most large series of clinical or scientific studies are from Chinese children and/or authors of Chinese origin.

Epidemiology

• High prevalence - 10-30% HBsAg carriers (1/2 are HBeAg+)
  • especially among lower socio-economic strata.

Natural History

• 40-50% carriers are from Maternal-Infant (Vertical) transmission.
• 90+% of infants born to HBeAg+ mothers get infected.
• 10% infected infants not only become chronic carriers, but also have high chance of chronic/active hepatitis and CA liver
• Spontaneous loss of HBsAg infrequent
• Sero-conversion of HBeAg occurs at 2%-5% annually, much slower in <3 yr old
• Sero-conversion from HBeAg+ to Anti-HBe may not necessarily be a good prognostic sign; liver pathology, like fibrosis, and cancer may still occur with 7% chance.
• Prolonged immunologic tolerance is a feature of early childhood disease
• Multiple exacerbations are associated with clearance phase of viral antigens; 2.4% chance of liver failure
• Liver cancers occur exclusively in HBsAg carriers around 37 yrs old
• 40% of cancer subjects show continuing HBV and delta infections

Prevention

• Early active immunization effectively protects for 10-15 years.
• Premies' immunologic response is less.
• Passive IgG effects not lasting.
• Intra-uterine infection is major cause of vaccine failure.

Treatment

• Anti-viral and immune-modulations including Interferon ± Prednisolone and several herbs have been reportedly useful.
• Lamivudine currently holds better promise.