In this study we used the same cohort of HIV infected patients of our recently published manuscript on HIV/HBV co-infection [22] to further investigate occurrence of OBI, and we found a prevalence of OBI of 8.3% in anti-HBc alone HIV infected patients, which was similar to that reported in other studies, but higher and lower frequencies had also been described elsewhere [25–31]. This evidence concerns the gene KRT88P and coinfection.