A Follow-up Study of Peginterferon Alfa-2b Combined With TDF in Patients With Chronic Hepatitis B

Inclusion Criteria: * Participants who completion of the TB1901IFN study ("completion" is defined as completion of more than 80% of trial medications (including peginterferon alfa and tenofovir disoproxil fumarate), or meeting criteria for early discontinuation and completion of consolidation therapy, as well as completion of discontinuation follow-up and 24-week post-discontinuation visit); * Voluntary enrollment, understand and sign the informed consent form. For cohort 1 only; - Subjects who have achieved functional cure (defined as the disappearance of HBsAg at the completion of TB1901IFN, with or without the appearance of HBsAb); For cohort 2 only: * At the completion of TB1901IFN, the S antigen level has decreased by ≥1 log compared to the baseline, with an S antigen level of less than 100 IU/ml, or the S antigen level has decreased by ≥1.5 log compared to the baseline, with an S antigen level of less than 1500 IU/ml; * Willing to accept the treatment of peginterferon combined with TAF; For cohort 3 only: \- Participants who have not achieved functional cure upon completion of TB1901IFN (defined as HBsAg ≥ 0.05 IU/ml)； Exclusion Criteria: \- Suspected or confirmed HCC patients. For Cohort 2 only: * Suspected or confirmed liver cirrhosis. * Pregnant, breastfeeding women, or those who plan to conceive during the combined medication treatment period. * Evidence of acute severe liver injury: e.g. ALT \> 10 times of the upper limit of normal (ULN), or a significant increase in ALT accompanied by a significant increase in bilirubin; * Evidence of decompensated liver disease: serum total bilirubin \> 2ULN, serum albumin \< 35 g/L, prothrombin time extended by more than 3 seconds beyond ULN, prothrombin activity \< 60%; or a history of decompensated liver cirrhosis; * Kidney disease: acute or chronic nephritis, renal insufficiency, nephrotic syndrome, etc., or serum creatinine \> 1ULN; * Neutrophil count \< 1.5×10\^9/L, platelet count \< 90×10\^9/L; * Severe retinopathy or other severe ophthalmic diseases; * Other conditions deemed by the investigator to be unsuitable for participation in the cohort 2. For cohort 3 only: \- Participants who plan to enter Cohort 2.