RESUMO
The changing pattern in hepatitis C virus (HCV) clades overtime is not well known in Pakistan. To find out the changing pattern of different HCV clades over time in this country 22,125 patients were genotyped and tracked for a period of 11 years (2000-2010). A changing pattern in HCV clades was seen in this region during the study period. Sub-clade 3a remained the dominant sub-clade circulating in different areas of the country in the study era. HCV sub-clade 3a demonstrated significantly high correlation with time (p < 0.05) whereas undetermined clades were seen with statistically non-significant correlation with time (years). All the other clades showed negative correlation with time. In general a significant decline was observed in the percentages of HCV clades 2, 4, 5 and 6 (p < 0.001). Among sub-clades, HCV 1a, 2c, 2b and 3b significantly decreased overtime (p < 0.05), while an increase has been observed for HCV 3a sub-clade and mixed clades (p <0.001). The ratio of undetermined clades remained constant over the study period. In conclusion, a changing pattern of HCV clades was observed over the 11-year study period, and this changed pattern might have direct impact on HCV disease outcome.