Response to Hepatitis B Vaccination in HIV and HCV Co-infected Adults: A 10-Year Retrospective Analysis

Purpose: Superinfection of acute hepatitis B (HBV) in individuals co-infected with human immunodeficiency virus (HIV) and chronic hepatitis C (HCV) has been associated with an increased mortality rate, and may accelerate the progression of chronic liver disease to cirrhosis, decompensated liver disease, and hepatocellular carcinoma. We hypothesized that co-infected patients might have a lower response rate to HBV vaccination, considering the immunosuppressive effect of combined HIV and HCV infection. This study compared immunogenicity of HBV vaccination in HIV/HCV co-infected patients to those having HIV and HCV mono-infection. Methods: A retrospective analysis was conducted at a tertiary academic hospital. HIV and HCV cases were identified based on their respective ICD-9 codes. All identified cases had completed the appropriate HBV vaccination series as defined by the Centers for Disease Control and Prevention. HBV seroconversion, or response to vaccination, was defined as individuals with a HBV surface antibody titer >10 IU/L within 6 months post-vaccination. Results: A total of 78 cases were reviewed over a period of 10 years. Twenty-six HIV/HCV co-infected individuals were identified and compared to an equal number of HIV and HCV mono-infected patients. The mean ages for the HIV/HCV co-infected group, the HIV group, and the HCV group were 48, 39, and 49, respectively. Males accounted for the majority in all three groups (64%). HBV seroconversion was 54% in the HIV/HCV co-infection group, 50% in the HIV group, and 65% in the HCV group (p = 0.48). Of the HIV/HCV co-infected group, 66% lost their immunity within 3 years post-vaccination. The mean CD4 count and CD4 nadir were lower in HIV/HCV non-responders vs. responders (CD4 mean ± SD of 433±275 vs. 596±269; CD4 nadir mean ± SD of 134±122 vs. 331±236). A similar observation was seen in the HIV group non-responders vs. responders (CD4 mean ± SD of 351±315 vs. 557±305; CD4 nadir ± SD of 205±315 vs. 394±252). There were more subjects with detectable HIV viral load (VL) in non-responders vs. responders in both the HIV/HCV group (41.6% vs. 28.5%) and the HIV group (31% vs. 77%). Conclusion: There is no difference in HBV immunogenicity in HIV/HCV co-infected individuals as compared to those with HIV alone. There is a higher response rate to HBV vaccination in HCV monoinfected patients, suggesting HCV infection has little or no effect on a co-infected individual's response to HBV vaccination. The CD4 count, CD4 nadir, and the VL may play a role in the immune response to the vaccine in patients with HIV. The majority of HIV/HCV co-infected individuals who achieved seroconversion lost their immunity within 3 years, which highlights the need for frequent titer monitoring and additional vaccination series.