(vi) Patients treated with chemotherapy and immunosuppressive therapy For HBsAg-positive patients treated with chemotherapy and immunosuppressive therapy (especially adrenal glucocorticoids) for other diseases, even if HBV DNA is negative and ALT is normal, lamivudine should be started 1 week before treatment at 100 mg daily, and after the cessation of chemotherapy and immunosuppressive therapy, lamivudine should be decided according to the patient’s condition The timing of discontinuation should be determined according to the patient’s condition after cessation of chemotherapy and immunosuppressive therapy. Those resistant to lamivudine may be switched to other approved nucleoside (acid) analogs that can treat resistant variants. Nucleoside (acid) analogues may be discontinued and relapse or even deterioration of the disease should be noted. (vii) Other special cases 1) Patients who do not respond to conventional IFN-α therapy: Patients who do not respond to conventional IFN-α therapy after standardized conventional IFN therapy have very low efficacy when conventional IFN therapy is applied again. PegIFNα-2a or nucleoside (acid) analogues can be tried. (2) Treatment of nucleoside (acid) analogs after the development of resistance mutations: Once resistance is detected, rescue therapy should be given as soon as possible. One study found that for patients treated with lamivudine, adding adefovir once genotypic resistance was detected or HBVDNA began to rise resulted in faster viral suppression, less drug resistance, and better clinical outcomes. There are relatively few clinical studies on the treatment of patients resistant to other drugs, and recommendations regarding treatment are based primarily on in vitro studies. Adefovir may also be added for those with resistance to telbivudine and entecavir. For those who are resistant to adefovir and have not taken other nucleoside analogues, lamivudine, entecavir or telbivudine may be added. （The indications, efficacy and safety of generic IFNα therapy in children over 12 years of age with chronic hepatitis B are similar to those in adults, with doses of 3-6 MU/m2 and a maximum dose of 10 MU/m2. lamivudine can also be used at the same dose and duration as adults on the basis of informed consent. (ix) Occult hepatitis B Antiviral therapy for patients with occult hepatitis B virus infection may be ineffective because most patients with occult hepatitis B virus infection have low HBV DNA levels. In contrast, antiviral therapy may be considered for the very few patients with occult hepatitis B who have persistently high serum HBV DNA and no other liver disease. Occult hepatitis B virus infection accounts for a certain proportion of patients with cirrhosis and hepatocellular carcinoma, and its prevalence varies in different parts of the world and with the technology used to detect HBV DNA. Future studies should elucidate the pathogenic role of occult hepatitis B virus infection and the basis of undetectable circulating HBsAg. Only by focusing on these important issues can all patients with HBsAg-negative liver disease be tested and treated with antiviral therapy for the detection of occult hepatitis B virus infection.