Hepatitis B virus (HBV) infection is a major public health problem and chronic HBV infection affects about 296 million people worldwide and is the leading etiology of cirrhosis and hepatocellular carcinoma globally. China takes up a great deal of the responsibility towards the goal of "eliminating viral hepatitis by 2030" released by the World Health Organization (WHO), as China has the world's largest burden of HBV infection. The current diagnostic rate barely reaches 24%, which is significantly short of the target diagnostic rate of 90% proposed by WHO. Progression from chronic hepatitis B (CHB) to hepatic complications-fibrosis, cirrhosis, and HCC-can be prevented significantly by preemptive antiviral therapy. However, the onset of CHB seldom manifests with typical symptoms, and most cases at their first diagnosis have progressed to end-stage liver diseases. Therefore, early detection of CHB and its complications that not only raises public awareness of preventing infection but also brings the patients into the management system is urgent blocking the progression to cirrhosis and HCC.

The study is a prospective and observational study involving community-based screening of chronic HBV infection and related liver diseases systematically among the general population of Guangdong Province, China. Individuals in Maoming City, aged 20-70 years, will be enrolled in the screening group for the HBsAg screening using a finger blood test. Positive participants will receive further examinations including laboratory and imaging examinations to discover HBV-related liver diseases. The control group will be enrolled from the general population in two similar cities.

By thoroughly investigating the epidemiological landscape and antiviral situation of chronic hepatitis B through population screening, this study intends to furnish the administration with updated epidemiological data. Additionally, the project seeks to establish a CHB screening cohort to enhance early diagnosis and treatment rates for both HBV-related liver diseases. Collectively, the study aspires to improve the overall prognosis for patients with chronic HBV infection, reduce CHB-related mortality, and ultimately put forward valuable healthcare insights and evidence-based medicine (EBM) practices for the effective implementation of CHB screening and management.

Sample selection Individuals aged from 20-70 years old who permanently reside in Maoming City will be enrolled in the screening group.

The natural population from another two cities which share economic, climatic, and customary similarities with Maoming City will be enrolled in the control group.

Participants recruitment Participants who voluntarily attend the screening project will be recruited to the screening group. Personal and medical information of the control group will be fetched from the Guangdong Provincial Center for Disease Control and Prevention, the Cancer Register, the Population Register, and other relevant systems.

Informed consent Informed consent forms will be collected at the recruitment in the screening group.

Questionnaires Questionnaires will be conducted face-to-face by well-trained investigators to gather the personal information of the participants in the screening group and inquire about the previous and current medical history of them and their families concerning viral hepatitis, cirrhosis, and HCC.

HBsAg screening test Participants in the screening group will firstly receive the HBsAg screening using a finger blood test.

Laboratory and imaging examinations Participants positive for the HBsAg screening test in the screening group will undergo further clinical examination to determine if their infections have developed CHB and even HCC. The laboratory examination includes blood routine tests (white blood cell count [WBC], red blood cell count [RBC], hemoglobin [HGB], platelet count [PLT]), liver function (total bilirubin [TBIL], albumin [ALB], alanine aminotransferase [ALT]), HBV serologic markers, alpha-fetoprotein (AFP), abnormal Prothrombin II (PIVKA II) and HBV-DNA. Patients with HBsAg-positive status undergo liver ultrasound examination. If suspicious liver nodules or elevated AFP levels are detected, further refinement through abdominal CT or MRI is recommended.

Inclusion Criteria:

1. Screening Group

   Individuals with all the following characteristics can be included:

   1. Aged from 20 to 70;
   2. From the residential population of Maoming City, Guangdong Province;
   3. Voluntarily participate and provide written informed consent forms.

2. Control Group

Individuals with all the following characteristics can be included:

1. Aged from 20 to 70;
2. From the residential population of Wuchuan City and Yangchun City, Guangdong Province.

Exclusion criteria:

1. Screening Group

   Individuals with all the following characteristics should be excluded:

   1. Floating population and temporary residents;
   2. Diagnosed with severe mental diseases who are unable to communicate normally;
   3. Determined by the researchers to be unsuitable for this study;

2. Control Group The control group data will be collected and organized through relevant systems such as the Guangdong Provincial Center for Disease Control and Prevention, the Cancer Register, and the Population Register, requiring no exclusion.

General population in Guangdong Province