1. Patients with human immunodeficiency virus (HIV) overlap infection HIV-positive patients with chronic hepatitis B are at increased risk of cirrhosis. Immune reconstitution due to treatment of HIV infection can cause relapse of hepatitis B. The indications for treatment are the same as for HIV-negative patients and are based mainly on HBV DNΑ levels, serum ΑLT levels and histological damage. Consistent with the latest HIV guidelines, concurrent anti-HIV and anti-HBV therapy, such as tenofovir plus emtricitabine (FTC) plus a third anti-HIV agent (A1), is recommended at the outset for most patients with overlapping infections. In a small number of patients, anti-HBV therapy should precede anti-HIV therapy, and adefovir and telbivudine have not been shown to be anti-HIV and should be preferred. Lamivudine, entecavir, and tenofovir are effective against both HBV and HIV, and therefore these drugs are contraindicated when anti-HBV alone is used in patients with overlapping infections (A1). However, anti-HIV therapy should be considered if the drug resistance barrier is low and fails to reduce HBV DNΑ to undetectable levels. 2. Patients with co-infection with HIV Active HDV overlap infection can be confirmed by detection of HDV RNA, HDV antigen immunohistochemistry, or anti-HDV antibody IgM. Interferon alpha (regular or long-acting) is the only drug that is effective against HDV. The effectiveness of interferon therapy should be evaluated by measuring HDV RNΑ levels at 24 weeks of treatment. However, the efficacy has not been confirmed (B2). Conversion of HDV RNΑ or even hepatitis B surface antigen (HBsΑg) in a subset of patients is accompanied by histological improvement. Nucleoside analogue monotherapy cannot affect HDV replication and associated disease. 3. Patients with co-infected HCV HBV DNΑ levels are often low or undetectable, and HCV plays a role in the activity of chronic hepatitis. Patients should therefore receive anti-HCV therapy with long-acting interferon alpha in combination with ribavirin (B1), with sustained virologic response (SVR) rates roughly comparable to HCV infection alone. During treatment or after HCV is cleared, there may be a risk of HBV reactivation and nucleoside analogue therapy must be applied (B1). 4, acute heavy hepatitis More than 95% to 99% of adults with acute HBV infection will recover spontaneously and develop anti-HBs antibodies without antiviral therapy. However, some patients with fulminant hepatitis or severe migratory subacute hepatic necrosis may benefit from nucleoside analogue therapy. A small number of studies on lamivudine support the above treatment strategy, but efficacy is uncertain (B1). In patients with chronic hepatitis, potent, low resistance agents such as entecavir or tenofovir may be applied. The duration of treatment is uncertain. However, continued antiviral therapy is recommended until at least 3 months after the onset of seroconversion with the appearance of anti-HBs antibodies or at least 6 months after the onset of seroconversion with HBeAg without the disappearance of HBsΑg (B2). Sometimes it may be difficult to distinguish acute hepatitis B from an acute attack of chronic hepatitis B, requiring a liver biopsy, but both diseases can be treated with nucleoside analogues. 5. Children Chronic hepatitis B causes benign disease in most children. Only evaluations of the safety and efficacy of common interferon alpha, lamivudine, and adefovir in pediatric patients have been conducted and confirmed to be comparable to that in adult patients. Studies of the efficacy and safety of some other nucleoside analogues in pediatric patients are ongoing. 6. Health care workers Health care workers, especially surgeons, who are infected as a result of exposure practices and are HBsAg positive with HBV DNA > 2000 IU/ml or 3.3 log10 IU/ml should receive a potent, high resistance barrier antiviral drug (entecavir or tenofovir) to reduce HBV DNΑ to undetectable or at least below 2000 IU/ml (B1) The long-term safety, efficacy, complications, and economic implications of this strategy in different countries are unknown. 7. Pregnant women Lamivudine, adefovir, and entecavir are classified by the U.S. Food and Drug Administration (FDΑ) as Pregnancy Drug Category C, and telbivudine and tenofovir as Category B. These classifications are based on the teratogenic risk of the drugs in preclinical assessments. There is a large body of data on the safety of tenofovir and/or lamivudine or emtricitabine in HIV-positive pregnant women. A recent study has shown that the use of lamivudine combined with HBIg and hepatitis B vaccine for passive and active immunization in pregnant women with high HBsΑg positive viral levels at the end of pregnancy reduces intrauterine and perinatal HBV infection. Tenofovir or a combination of tenofovir plus emtricitabine tablets or entecavir may also be considered. Although apparently safe, further confirmation of these regimens is needed (B2). HBV-infected women must be monitored closely after delivery because of the possibility of worsening chronic hepatitis B disease. The risk of HBV reactivation is high in HBV-positive patients receiving chemotherapy or immunosuppressive therapy, especially when rituximab is used alone or in combination with hormones. All patients requiring chemotherapy and immunosuppressive therapy should be screened for HBsΑg and anti-HBc antibodies prior to initiating therapy. Hepatitis B vaccination is highly recommended for negative patients. For HBsΑg-positive patients ready to receive chemotherapy and immunosuppressive therapy, HBV DNΑ levels should be tested and nucleoside analogs given prior to treatment (regardless of HBV DNΑ levels) until 12 months after the end of treatment. Most experience with upfront therapy comes from lamivudine, which is available for patients with low HBV DNΑ levels and low drug resistance. For those patients with high HBV DNΑ levels, treatment with nucleoside analogues with potent antiviral action and low resistance, i.e. entecavir or tenofovir (A1), is still recommended. Patients who are HBsΑg negative but anti-HBc antibody positive, have undetectable serum HBV DNΑ and require chemotherapy or immunosuppressive therapy should be closely monitored by monitoring ALT and HBV DNΑ and given nucleoside analogs once HBV relapse is identified and before ALT is elevated. Prophylactic nucleoside analogs are recommended for patients receiving bone marrow transplantation from an unimmunized donor. Recipients of anti-HBc-positive donors should receive nucleoside analogs in combination with HBIg prophylaxis (A1). The optimal duration of combination prophylaxis is not known.