Chronic hepatitis B can develop into cirrhosis and liver cancer, which seriously endangers the life and health of people. In China, HBV is mainly transmitted from mother to child, showing the phenomenon of family clusters. Similarly, cirrhosis and hepatocellular carcinoma occur in familial clusters. Familial clusters of HBV infection with unfavorable prognoses refers to HBV-infected patients from two consecutive generations of blood relatives, with at least one family member diagnosed with hepatitis B-related cirrhosis or hepatocellular carcinoma (HCC). Previous family investigations have shown that the risk and harm of HBV-related cirrhosis and hepatocellular carcinoma are significantly higher in families with familial clusters of HBV infection with unfavorable prognoses than in the general population. Currently, antiviral drugs used for CHB mainly include nucleoside analogues (NAs) and interferon-alpha (mainly pegylated interferon-alpha, Peg IFN). NAs mainly inhibits viral replication by blocking the reverse transcription process, but it cannot effectively inhibit the expression of viral proteins such as HBsAg, and rarely achieves clinical cure. Multiple clinical studies have shown that the use of NAs reduces the incidence of cirrhosis decompensation, HCC, and death in patients with CHB compared to untreated or placebo-treated patients. Despite long-term treatment with first-line NAs drugs, CHB patients continue to be at risk of developing hepatocellular carcinoma. Peg IFN α-2b injection is the first-line drug of choice for antiviral treatment of chronic hepatitis B, and its main mechanism of action includes anti-HBV, anti-fibrosis, anti-tumor and regulation of immune response. In 2024, a randomized controlled multicenter study showed that Peg IFN α-2b combined with NAs therapy could effectively prevent hepatocellular carcinoma in CHB patients. There is sufficient evidence in clinical practice that long-term antiviral therapy, whether NAs or Peg IFN α-2b, reduces the risk of cirrhosis, hepatocellular carcinoma, and death in patients with CHB. In conclusion, early antiviral therapy can reduce the risk of developing hepatitis B cirrhosis and hepatocellular carcinoma in CHB patients with familial clusters of HBV infection with unfavorable prognoses. The goal of this observational study is to explore the evaluation of pegylated interferon α-2b combined with first-line NAs on the long-term outcome of CHB antiviral therapy with cirrhosis and HCC progression as the main observation targets, compared with only use of NAs in the context of familial clusters of HBV infection with unfavorable prognoses. It is intended to provide high-quality evidence-based medical evidence for the treatment and follow-up of CHB, explore optimal clinical decision-making, and provide global clinical data for the improvement and evaluation of this difficult-to-treat population. The main question it aims to answer is: Can Peg IFN-α-2B combined with NAs therapy improve the long-term outcomes of this particular population of familial clusters of HBV infection with unfavorable prognoses compared to first-line NAs monotherapy? Patients with familial clusters of HBV infection with unfavorable prognoses using Peg IFN-α-2B combined with NAs therapy and NAs monotherapy will be collected laboratory and medical examination data at specified follow-up points, and recorded adverse events and drug combinations in detail for 7 years.