Prevalence and Pattern of Resistance in NS5A/NS5B in Hepatitis C Chronic Patients Genotype 3 Examined at a Public Health Laboratory in the State of São Paulo, Brazil.

Purpose: Globally, it is estimated that 71 million people are chronically infected with hepatitis C, and 10-20% of these will develop cirrhosis and hepatocellular carcinoma. The development of new direct-acting antiviral (DAA) drugs has contributed to sustained virological response (SVR), eliminating the infection and achieving cure of chronic hepatitis C. However, treated patients can develop HCV resistance to DAAs, which can contribute to the failure of treatment. Here, we aimed to evaluate the prevalence and specific pattern of NS5A and NS5B resistance-associated substitutions (RAS) in samples from patients chronically infected with HCV genotype 3a at a public health laboratory, Instituto Adolfo Lutz, São Paulo, Brazil.

Patients And Methods: Serum samples from the enrolled individuals were submitted to "in-house" polymerase chain reaction amplification of NS5A and NS5B non-structural protein genes, which were then sequenced by Sanger method.

Results: A total of 170 and 190 samples were amplified and analyzed for NS5A and NS5B, respectively. For NS5A, 20 (12.0%) samples showed some important RAS; 16 (9.0%) showed some type of substitution and 134 (79.0%) showed no polymorphism. No sample showed any RAS for NS5B.

Conclusion: This study found important RAS in samples from naïve chronic HCV patients in some areas from São Paulo. The most prevalent were A62S, A30K, and Y93H, which could indicate an increase in resistance to some DAAs used in HCV treatment.