The most appropriate management is ultrasound imaging of the liver every 6 months. This patient from Africa has evidence of chronic hepatitis B virus (HBV) infection. In approximately 50% of untreated patients with chronic HBV infection in the United States, HBV will contribute to the cause of death (from hepatocellular carcinoma [HCC] or other complications of end-stage liver disease, such as cirrhosis). HCC surveillance is advised in African patients over the age of 20 years with chronic HBV infection. Screening and surveillance for HCC consist of cross-sectional imaging with ultrasound, CT, or MRI. Ultrasound is the most widely available and least expensive imaging modality and is preferred. For patients with normal imaging at diagnosis, the recommended interval for surveillance imaging is 6 months. Serum α-fetoprotein measurement does not have sufficient diagnostic accuracy alone to be a valuable tool for early detection. The combination of ultrasonography and α-fetoprotein measurement increases cancer detection rates, but this comes at the expense of increased false-positive findings. Other indications for HCC surveillance in patients with chronic HBV infection are (1) patients with cirrhosis, (2) Asian men older than 40 years, (3) Asian women older than 50 years, (4) patients with a family history of HCC, and (5) patients with persistent hepatocellular inflammation (defined as elevated alanine aminotransferase [ALT] level and HBV DNA level greater than 10,000 IU/mL).

This patient has already been infected with HBV, so vaccination at this point will not be effective.

This patient's HBV infection is in the inactive carrier/immune control state, as evidenced by his normal ALT level and HBV DNA level below 10,000 IU/mL. Treatment with antiviral agents such as pegylated interferon or tenofovir is not necessary for patients in the inactive carrier state. However, surveillance for HCC is still indicated.