Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPSANTOS, Ana Paula de TorresSILVA, Vanessa Cristina MartinsMENDES-CORREA, Maria CassiaLEMOS, Marcilio FigueiredoMALTA, Fernanda de MelloSANTANA, Rubia Anita FerrazDASTOLI, Gregorio Tadeu FernandoCASTRO, Vanessa Fusco Duarte dePINHO, Joao Renato RebelloMOREIRA, Regina Celia2022-12-212022-12-212022REVISTA DO INSTITUTO DE MEDICINA TROPICAL DE SAO PAULO, v.64, article ID e61, 9p, 20220036-4665https://observatorio.fm.usp.br/handle/OPI/50561The Hepatitis C virus (HCV) infection is a public health problem. The high level of HCV replication and its lack of post-transcriptional correction mechanisms results in the emergence of viral variants and the difficulty in determining polymorphisms and variants that contain the substitutions associated with resistance towards new antivirals. The main focus of this study was to map the NS5A and NS5B polymorphisms and resistance mutations to new antiviral drugs in HCV strains genotype 1 from patients with chronic hepatitis C infection. Serum samples were collected from patients who underwent routine viral load tests at the Instituto Adolfo Lutz, Sao Paulo city, Brazil. A total of 698 and 853 samples were used for the characterization of NS5A and NS5B regions, respectively, which comprise the HCV genotypes la and lb. The prevalence of resistance mutations found in the NS5A region was 6.4%, with Y93H, L31M, Q30R, and Y93N as the main resistance-associated substitutions (RAS). No NS5B-associated RAS was observed for any of the analyzed drugs. These findings support that the RAS test should be offered to individuals with poor response to double combination regimens prior to treatment initiation, thereby assisting strain vigilance and selection of effective treatment or retreatment options using DAA regimens.engopenAccessDAAHepatitis C virusGenotype 1RASNS5BNS5AhcvsubstitutionsepidemiologyinhibitorsvariantsimpactarticleCopyright INST MEDICINA TROPICAL SAO PAULO10.1590/S1678-9946202264061Infectious DiseasesParasitologyTropical Medicine1678-9946