Invited Commentary: Screening for hepatitis B in the immigrant population and individuals who are in need of immunosuppressive drug therapy.

Chronic hepatitis B (CHB) afflicts approximately 300 million people in the world. Hepatitis B virus (HBV) is a known carcinogenic virus and continues to be the leading cause of hepatocellular carcinoma (HCC) (1). Approximately 70% of hepatitis B surface antigen (HBsAg) carriers reside in intermediate (>2% prevalence) to high-risk (>8% prevalence) areas such as Asia, the Pacific Islands, Africa, India, and parts of Southern Europe (1). There is a common misperception that this disorder is not very common in the United States. However, 63% of the nearly 28 million immigrants who entered the US between 1974 and 2008 were born in countries of intermediate or high prevalence (2). The Immigrant Refugee and Migrant Health Branch of the Centers for Disease Control and Prevention (CDC) estimated that an average of 53,000 CHB cases were imported to the US yearly from 2004 to 2008. Forty percent of these cases originated from China, Vietnam, and the Philippines (2). The CDC has recently revised its prevalence estimates and concluded that 2.2 million US residents are likely to have chronic HBV infection, of which 1.3 million are judged to be foreign-born individuals. Even these figures are likely to be too low, however, because the estimates do not take into account illegal immigrants and other socially disadvantaged patients. Importantly, HBsAg testing is not required as part of the process of immigrating into the United States (3). This lack of a requirement for HBV screening is an important missed opportunity to programmatically diagnose this condition.