Molecular Epidemiology of HCV Infection among Multi-Transfused -Thalassemia Patients in Eastern India: A Six-Year Observation

Background: HCV infection is very common in multi-transfused beta-thalassemia patients who need regular blood transfusions. Aim: The study was conducted to determine the epidemiology of HCV in multi-transfused beta-thalassemia patients in West Bengal, India. Methods: Over a span of six years, blood samples were collected from HCV sero-reactive beta-thalassemia patients and processed for viral RNA isolation followed by nested RT-PCR for qualitative viremia detection. The HCV genotype was determined by amplifying the partial HCV core gene by nested RT-PCR followed by DNA sequencing and NCBI genotyping tools. Phylogenetic and phylogeographic studies were performed with MEGA-X and BEAST software, respectively. Results: Out of 917 multi-transfused HCV sero-reactive beta-thalassemia patients, 598 (65.21%) were HCV RNA positive while 250 (41.80%) had spontaneously cleared the virus. A significant percentage of male patients from rural areas (p = 0.042) and economically backward class (p = 0.002) were at higher risk of HCV infection. Female thalassemia patients and individuals belonging to ages 11-15 years had higher chances of spontaneous clearance. The most prevalent circulatory HCV genotype was 3a (78.26%) followed by 1b (12.04%). Phylogeographic analyses revealed that the 3a strains share genomic similarities with strains from Pakistan, Sri Lanka, and Thailand, whereas the 1b strains share similarities with strains from Thailand, Vietnam, Russia, and China. Uncommon HCV subtypes 3g and 3i were also detected. Conclusion: The high prevalence of HCV infection among beta-thalassemia patients of West Bengal, India indicates NAT-based assays should be implemented for HCV screening in donor blood to eliminate HCV by 2030.