Schematic representation of the natural history of perinatally acquired chronic HBV infection. This form of infection consists of 3 phases:
- Immune-tolerant – This phase lasts for months, years, or decades and is characterized by high levels of HBV replication, as manifested by the presence of HBeAg and high levels of HBV DNA in serum but no evidence of active liver disease, as manifested by normal serum ALT concentrations.
- HBeAg-positive immune-active (clearance) – During this phase, serum ALT is elevated and HBeAg seroconversion may occur.
- Inactive chronic HBV – This phase is usually characterized by the absence of HBV DNA and normalization of serum ALT. It is also known as the latent, nonreplicative or carrier phase. Some patients reactivate into the immune-active phase or HBeAg-negative HBV.
