Transient Hepatitis B Surface Antigenemia After Hepatitis B Virus Vaccine in an HIV-Infected Patient

Abstract

E ditor: Hepatitis B screening and vaccination are part of the standard of care in HIV-infected patients. The reasons for this recommendation are 2-fold. On the one hand, being infected with HIV is a risk factor for hepatitis B virus (HBV) infection as the two viruses share routes of transmission. On the other hand, the presence of HBV coinfection may influence the timing of highly active antiretroviral therapy (HAART) initiation and the HIV regimen chosen, as it must include agents with anti-hepatitis B activity. We present here a case that stimulated discussion regarding the interpretation of HBV serologies and the timing for HBV vaccination in the HIV-infected population. A 39-year-old African-American female was referred to our HIV clinic for initial evaluation after being diagnosed with HIV infection at the local health department. Bipolar disorder was her only significant past medical history. Three days earlier, as part of her initial HIV care at the health department, she received the first dose of Twinrix [a recombinant hepatitis A and hepatitis B vaccine containing inactivated hepatitis A virus (strain HM175) and noninfectious hepatitis B virus surface antigen (HBsAg)]. No hepatitis serologies were obtained prior to vaccination. This is consistent with local health department policy based on costbenefit estimates.At her first visit to our clinic, a hepatitis serology panel was obtained. The hepatitis A IgG, hepatitis B core IgG, hepatitis B surface IgG, and hepatitis C IgG were all nonreactive. Hepatitis B surface antigen was reactive. The serum HIV RNA level was 295 copies/ml, the CD4 count was 690 cells/mm 3 , and the complete blood count and comprehensive metabolic panel were within normal limits. The patient was contacted with the results, and she reported that she was asymptomatic. A serum HBV DNA obtained at that time was undetectable ( < 29 IU/ml). Since the laboratory results were not consistent with acute or chronic HBV infections, HBsAg was repeated upon her return to the clinic 4 weeks later, which was nonreactive. Clarification of the patient's HBV status was important as patients with HIV and HBV coinfection require special consideration regarding antiretroviral therapy and continued follow-up of liver status. For HBsAg testing our laboratory uses the AD-VIA Centaur instrument and follows the manufacturer's recommendations for reporting a positive result. The ADVIA Centaur HBsAg assay is a sandwich immunoassay using direct, chemiluminometric technology and uses index values to determine reactivity. Samples with index values of 1.0 to 50.0 are weakly positive and are retested in duplicate prior to reporting the positive value.A reactive HBsAg in the HIV-infected patient most often represents chronic HBV infection. However, in the reported case the hepatitis B core IGG was negative. Isolated hepatitis B surface antigenemia can occur early in hepatitis B infection or as we will describe as a postvaccination phenomenon. Based on the available information, this patient was most likely not infect...