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The time between the removal of the HBsAg and the appearance of anti-HBs is called the window period. A person negative for HBsAg but positive for anti-HBs either has cleared an infection or has been vaccinated previously. Individuals who remain HBsAg positive for at least six months are considered to be hepatitis B carriers. [68]
It is produced by yeast cells, into which the gene for HBsAg has been inserted. [65] Afterward an immune system antibody to HBsAg is established in the bloodstream. The antibody is known as anti-HBs. This antibody and immune system memory then provide immunity to hepatitis B virus (HBV) infection. [71]
The genome organisation of HBV; the genes overlap. ORF S, in green, encodes HBsAg. HBsAg under a transmission electron microscope: the protein self assembles into virus-like particles. HBsAg (also known as the Australia antigen) is the surface antigen of the hepatitis B virus (HBV). Its presence in blood indicates existing hepatitis B infection.
If HBsAg is present, a second test – usually done on the same blood sample – that detects the antibody for the hepatitis B core antigen (anti-HBcAg) can differentiate between acute and chronic infection. [84] [88] People who are high-risk whose blood tests negative for HBsAg can receive the hepatitis B vaccine to prevent future infection.
HBeAg is produced by proteolytic processing of the pre-core protein. The DNA polymerase is encoded by gene P. Gene S is the gene that codes for the surface antigen (HBsAg). The HBsAg gene is one long open reading frame but contains three in frame "start" (ATG) codons that divide the gene into three sections, pre-S1, pre-S2, and S. Because of ...
HBIG should be given within 14 days of exposure to the hepatitis B virus. [7] The half-life of HBIG is about 3 weeks. In lieu of a booster administration of HBIG, a hepatitis B vaccination is initiated at the time of the initial HBIG administration, thus providing long term protection.
Viral hepatitis is liver inflammation due to a viral infection. [1] [2] It may present in acute form as a recent infection with relatively rapid onset, or in chronic form, typically progressing from a long-lasting asymptomatic condition up to a decompensated hepatic disease and hepatocellular carcinoma (HCC).
An individual with a chronic infection would test positive for HBsAg and total anti-HBc (IgM and IgG), but negative for IgM anti-HBc and anti-HBs. An individual who has successfully resolved their HBV infection will test negative for HBsAg, positive for anti-HBc, and may test negative or positive for anti-HBs, although most will test positive ...