HBsAg

Infants born to HBsAg-positive mothers should receive hepatitis B vaccine and 0.5 mL hepatitis B immune globulin (HBIG) within 12 hours of birth at separate sites. The second dose is recommended at age 1-2 months and the vaccination series should be completed (third or fourth dose) at age 6 months. 

Infants born to mothers whose HBsAg status is unknown should receive the first dose of the hepatitis B vaccine series within 12 hours of birth. Maternal blood should be drawn at the time of delivery to determine the mother s HBsAg status if the HBsAg test is positive, the infant should receive HBIG as soon as possible (no later than age 1 week). 

Lok and McMahon 2007), but the ideal outcome is undetectable HBV DNA (< 10-30lU/ml) in highly sensitive real-time PCR-based assays. In HBeAg-positive patients, loss of HBeAg followed by the emergence of anti-HBe antibodies ( e seroconversion) indicates a sustained response to therapy when it persists after treatment cessation. HBs seroconversion (loss of HBsAg and emergence of anti-HBs antibodies) is the most desirable endpoint, as it indicates a complete response with sustained remission from HBV disease. It is rarely achieved with cnrrent therapies. 

Worldwide, 15 million HBsAg carriers are also infected with hepatitis D/delta virus (HDV) (Gaeta et al. 2000). This situation represents a major therapentic challenge, as most of these patients have advanced liver disease, inclnding cirrhosis in 60-70% of cases, and hepatocellular carcinoma (Fattovich et al. 2000 Saracco et al. 1987). No specific HDV inhibitors have been developed, and IFN-a-based treatment is more difficnlt in HBV-HDV infection than in HBV monoinfection. HDV RNA levels in sernm can be nsed to monitor treatment efficacy. The endpoint of therapy is HDV RNA clearance and ALT normalization, and this is sometimes achieved after the end of treatment. A snstained response can lead to HBsAg clearance from serum. 

Flink HJ, van Zonneveld M, Hansen BE, de Man RA, Schalm SW, Janssen HL (2006b) Treatment with Peg-interferon alpha-2b for HBeAg-positive chronic hepatitis B HBsAg loss is associated with HBV genotype. Am J Gastroenterol 101 297-303... 

Saracco G, Rosina F, Brunetto MR, Amoroso P, Caredda F, Farci P, Piantino P, Bonino F, Rizzedo M (1987) Rapidly progressive HBsAg-positive hepatitis in Italy. The role of hepatitis delta virus infection. J Hepatol 5 274-281... 

The serum from patients with clinical symptoms of hepatitis B commonly contain three distinct structures that possess HBsAg (section 3.8.5 above). The effects of different concentrations of various disinfectants on the structure of Dane particles have been studied, but it is unlikely that morphological changes can be related to virucidal activity. 

Hepatitis Bt Yeast cells genetically modified to express surface antigen 1 Separation of HBsAg from yeast cells 2 Adsorption to AI(0H)3 gel Immunogenicity assay or HBsAg assay by ELISA Test for presence of yeast DMA... 

Hepatitis B is diagnosed when HBsAg is detectable in the serum. The nucleocapsid of the HBsAg contains the core protein that produces HBcAg, which is undetectable in the serum. The presence of antibodies against anti-HBc to IgM indicates active infection, and anti-HBc to IgG relates to either chronic infection or possible immunity against HBV. 

May be recovering from acute HBV infection (2) May be distantly immune and test is not sensitive enough to detect very low level of anti-HBs in serum (3) May be susceptible with a false-positive anti-HBc (4) May be undetectable level of HBsAg present in the serum and the person is actually a carrier. 

The two hepatitis B vaccines available in the United States are Recombivax HB and Engerix-B. These vaccines are produced with recombinant DNA technology by inserting the gene for HBsAg into the plasmid that is synthesized by Saccharomyces cerevisiae cells. Both vaccines are effective in providing... 

Postexposure prophylaxis for perinatal exposure depends upon the mother s HBsAg status.24 Mothers who are HBsAg-positive should have their newborns immunized with both the hepatitis B vaccine and HBIG 0.5 mL. This regimen is 85% effective in preventing the hepatitis B carrier status if administered... 

Exposed Person s Vaccination Status HBsAg Positive HBsAg Negative Unknown or Unavailable for Testing... 

Previously vaccinated Known responder Known non-responder Antibody response unknown No treatment HBIG x 1 and initiate HB revaccination or HBIG x 2 Test exposed person for anti-HBs (1) if adequate, no treatment (2) if inadequate, HBIG x 1 and vaccine booster No treatment No treatment No treatment No treatment If known high-risk source, treat as if source were HBsAg-positive Test exposed person for anti-HBs (1) if adequate, no treatment (2) if inadequate, vaccine booster and recheck titer in 1-2 months... 

HB, hepatitis B anti-HBs, hepatitis B surface antibody HBsAg, hepatitis B surface antigen HBIG, hepatitis B immune globulin. 

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