The burden of chronic hepatitis B infection in china
Worldwide, an estimated two billion people have been infected with the hepatitis B virus (HBV) and, of these, nearly 400 million remain chronically infected [1, 2]. About one-third of those with chronic hepatitis B (CHB) infection live in China, where it is estimated that around 100 million people (about 10% of the Chinese population) are chronically infected, and around 500,000 people die from CHB-related complications, including primary liver cancer (hepatocellular carcinoma, HCC) and cirrhosis, each year [3–6]. China has the highest age-adjusted incidence (new cases) of HCC due to CHB, and about 55% of liver cancer deaths worldwide occur in China [7]. Most of these deaths are men in their prime, between the ages of 30 and 65 years. Up to 9.5% of Chinese women of childbearing age have CHB [8]. Newborns infected perinatally have a more than 90% risk of developing CHB infection, and thus have an increased risk of premature death from end-stage liver disease or liver cancer [9, 10]. Of babies born to HBV-infected mothers, 5% to 10% become chronically infected despite receiving immunoprophylaxis with Hepatitis B immune globulin (HBIG) and hepatitis B vaccine [11].
There are significant unmet needs for millions of individuals living with CHB, including a lack of screening and diagnosis, and limited access to appropriate medical care and treatment. The Hepatitis B Foundation (HBF) believes that the burden of CHB can be reduced, and lives saved, through improved public awareness, health education, and screening. To this end, HBF launched the “Gateway to Care Campaign: Haimen City Project” in August 2010, in collaboration with the Haimen City Center for Disease Control and Prevention (HCCDC). This three-year project consisted of a targeted citywide public health information campaign; specialized health education and training for providers; establishment of health care infrastructure and management systems; and increased screening, vaccination, treatment, and care management service delivery to key subpopulations (especially pregnant women and their infants and families).
The Haimen City cohort
Haimen City is located in Jiangsu Province, approximately 60 miles northwest of Shanghai, with a total population of 1.03 million. HCC has been the leading cause of cancer death in this population since 1970 (when death registration began), and the incidence and mortality of HCC in Haimen City are among the highest in China, and in the world (Haimen City CDC Vital Statistics, unpublished data). A landmark study of this population published in 2006 clearly established a direct link between hepatitis B viral load and subsequent risk of liver cancer in chronically infected individuals [12]. This population-based prospective cohort study, begun in 1992, enrolled more than 90,000 Haimen City residents aged 25 to 64 years old. Blood tests for the presence of the hepatitis B surface antigen (HBsAg) indicated a 13.7% HBV infection rate of the cohort. Intensive follow-up, including annual collection and validation of vital statistics of each cohort member, has been conducted since 1994. Between 1994 and 2007, there were 7,468 deaths in the cohort, of which 1,717 (23%) were due to HCC.
Critical gaps in knowledge and practice
Previously published findings from this cohort have contributed to global knowledge regarding the outcome of chronic HBV infection. Although evidence-based HBV prevention, treatment, and management protocols have been published [13–17], evidenced-based guidelines have not been implemented in Haimen City. Huge gaps in knowledge and practice persist in the general population, among patients, and at every level of health care providers in Haimen City. City public health officials estimate there are approximately 80,000 people between the ages 25 to 64 years in Haimen City with CHB. Thousands will likely die from HCC and other chronic liver diseases within the next ten years if no appropriate actions are taken towards the prevention and control of HBV in this population.