- Age
The earlier the disease is acquired, the greater the chance of developing chronic hepatitis B infection.
+ Infants (mainly infected through vertical transmission) 90%
+ Children 25-50%
+ Adults ~ 5%
+ Elderly persons ~ 20-30%

- Clinical course: Acute------------>Chronic--------->Cirrhosis----------->HCC
+ Acute
Phisical:
* Low-grade fever
* Jaundice (10 d after the appearance of constitutional symptomatology and lasting for 1-3 mo)
* Hepatomegaly (mildly enlarged soft liver)
* Splenomegaly (5-15%)
* Palmar erythema (rarely)
* Spider nevi (rarely)
Subclinic:
* ALT > AST, ~ 1000-2000 UI/L
* Alkaline phosphatase (ALP) elevates < 3 times
* PT prolongation
* Markers: HBsAg (+), HBeAG (+), IgM anti HBc (+), if recover, seroconversion: Anti HBs (+), anti HBe (+), IgG anti HBc (+), if HBsAg (+) for > 6 mths --> develop chronic hepatitis
+ Chronic
Phisical:
* Hepatomegaly
* Palmar erythema
* Spider angioma
Subclinic:
Chronic inactive:
- AST, ALT: normal
- HBeAg (-), HBV DNA ~ 10^2-10^4 copies/ml
Chronic active:
- ALT > AST, ALT is extremely high
- HBV DNA > 10^5 copies/ml
- HBsAg (+), IgM HBc (+) or IgM HBc (+) if reactive