Background: Occult Hepatitis C Infection (OCI) is characterized by the detection of Hepatitis C Virus (HCV) RNA in hepatocytes and in Peripheral Blood Mononuclear Cells (PBMCs) with no detection in serum, and PBMCs and Red Blood Cells (RBCs) were more recently suggested as predictors for OCI characterization. Here we aimed to evaluate OCI in Kidney Transplanted Patients (KTRs) and in Hemodialysis Patients (HD) treated with Direct-Acting Antivirals (DAAs) five to nine years after achieved a Sustained Virological Response (SVR).

Methods: Nineteen patients-SVR12 were included in this study, 12 in the KTRs and 7 in the HD study groups. HCV/OCI-RNA was screened in serum, plasma, PBMCs and RBCs five to nine years after SVR by droplet digital PCR (ddPCR) for OCI identification. Next-Generation Sequencing (NGS) was performed to characterize the viruses detected by ddPCR.

Results: In total, OCI (10.5%) and OCI RBCs (15.8%) patients were identified by ddPCR, 8.3% (both) of OCI (patient 7) and OCI RBCs (patient 9) in the KTRs, and 14.3% and 28.6% of OCI (patient 17) and OCI RBCs (patient 13 e 16) in the HD patients, respectively. HCV/OCI-RNA higher detection was in RBCs-HD (28.6%, n = 7) and PBMCs-KTRs (16.7%, n = 12) by ddPCR. HCV/OCI-RNA was not detected in analyzed samples by NGS.

Conclusion: OCI and OCI RBCs patients were identified in the KTRs and HD study groups by ddPCR suggesting that these patients might experience a relapse. PBMCs and RBCs could be predictors for HCV/OCI prevention, diagnosis and management in the study groups. These and a larger number of patients in both study groups should be evaluated in the future for a better understanding of these findings, as well as, their associated epidemiological and clinical significance.