HBV-DNA is the most important indicator of the infectiousness of the virus, the higher the level of HBV-DNA, the more infectious it is. Another indicator of infectiousness is the e antigen (HBeAg), because HBeAg is the core part of the virus particles, the more virus particles, the higher the HBeAg, and the higher it is, the more active the virus replication is, and the more infectious it is. In addition, the former S1 and S2 proteins are the outer membrane proteins of the virus, and their positivity also suggests that the virus is actively replicating and is highly infectious. Anti-HBc-IgM is a diagnostic indicator of acute hepatitis B and active viral replication, and its positivity suggests high infectiousness.