This is a prospective observational study of CHB patients who have not received antiviral treatment but HBV DNA are positive.Investigators aim to explore the antiviral effect and influencing factors of patients over 30 years old with normal ALT level after receiving antiviral treatment.

In the past, clinicians thought that patients with chronic hepatitis B with normal ALT should be followed up regularly and not be treated with antiviral therapy for the time being, but more and more studies show that if antiviral therapy is not started in time, these patients still have a relatively high risk of cirrhosis and HCC. Therefore, the current Chinese guideline recommends that patients over the age of 30 with HBV DNA positive need antiviral treatment even if their ALT levels are normal. In this study, investigators aim to observe the antiviral effect of CHB patients above 30 years old and normal liver function. CHB patients were divided into NAs （TMF, ETV, or TAF) treatment and untreated groups for follow-up. Then, participants who achieved HBV DNA negative and HBsAg <3000 IU/ml after 12 weeks of NAs therapy could choose either NAs combined with 48 weeks of pegylated interferon α-2b(Peg-IFNα-2b) therapy or continue NAs monotherapy. Follow-ups were conducted every 12-24 weeks for a total duration of 96 weeks. Dynamic observations included monitoring virological markers,biochemical indicators,liver stiffness measurement(LSM),and controlled attenuation parameter(CAP) throughout the study period. After obtaining the informed consent of participants, the serum of participants and PBMC of some participants were collected for further study,so that investigators are able to explore the serological indexes related to curative effect and the immune function of participants before and after treatment.

Inclusion Criteria:

1. CHB patients over 30 years old ；
2. HBV DNA >20IU/ml and ALT level ≤40U/L；
3. All of them have never received any antiviral treatment(including NAs and interferon-α）。

Exclusion Criteria:

1. pregnancy status;
2. Patients with compensated/decompensated cirrhosis and liver cancer have been diagnosed by imaging or other indicators;
3. HCV, HIV, EB virus/cytomegalovirus infection, schistosomiasis liver disease, drug-induced liver injury, autoimmune hepatitis and alcoholic liver disease;
4. Use immunosuppressants ;
5. Previous history of liver cancer, organ transplantation and alcoholism (male ≥30 g/d, female ≥20 g/d);
6. Insufficient follow-up time and imperfect clinical/laboratory informations;
7. Combined with other major diseases.

The research population is CHB patients who have never received antiviral treatment and come to Tongji hospital for consultation and reexamination.