A comprehensive five-year study of Hepatitis C Virus infection and its transmission dynamics in multi-transfused β-globin defective patients in the state of West Bengal, India

Post transfusion acquired HCV infection is common in high risk group individuals such as b-thalassemia patients who depend on regular blood transfusions. This study was conducted to determine the prevalence, genotype distribution, transmission dynamics and correlation of patient age and gender with spontaneous clearance of HCV in multi-transfused b-thalassemia patients, in the state of West Bengal, India. HCV RNA was first detected, using RT-PCR, from serum samples collected from HCV seropositive b-thalassemic individuals over five years. Viral RNA was further sequenced, and genotyped, using NCBI genotyping tool, for phylogenetic and phylogeographic studies using MEGA-X and BEAST package 1.10.0, respectively. Out of 777 HCV seropositive b-thalassemic patients, 503 (64.73%) were positive for HCV RNA, while 274 (35.26%) had spontaneously cleared the virus. Female thalassemic patients and patients belonging to ages 10-14 years, had a higher chance of spontaneously clearing the virus. The most prevalent HCV genotype in this study population was 3a (77.61%) followed by 1b (11.94%). Phylogeographic analyses revealed that the 3a strains migrated from countries like Pakistan, China Myanmar and Thailand whereas the 1b strains transmitted from Bangladesh and Myanmar. The prevalence of HCV infection is very high among Indian b-thalassemic patients, which necessitates a critical look into the prevailing transfusion practices and requires implementation of more rigid donor screening criteria to decrease the rate of transfusion transmitted HCV infection, especially in the highly susceptible thalassemic patients. The use of more sensitive NAT based assays for HCV detection in donor blood is a compressing need of the hour.