Figure 4.

A graph is illustrating the pathogenic events throughout HBV infection. HBsAg can be detected very early in the acute course of infection and starts declining in serum to undetectable levels within 23–24 weeks post infection. The HbeAg is next and indicates the ability to infect others. The first HBV antibody produced is HBc IgM, and it may persist until 28 months post infection. Hence, detection of IgM represents an acute HBV infection. However, in the chronic infection phase, IgG becomes detectable and persists for a more extended period than IgM. During the recovery period, anti-HBs will not appear for a few weeks after HBsAg has been cleared. It is possible for both HBsAg and anti-HBs to be negative during recovery. This is called the window period in acute infection. Later, anti-HBs will be developed, and the immune system develops immunity as a result of an actual infection.