Estudo epidemiológico das vias de transmissão do vírus da hepatite C e resposta ao tratamento segundo a genotipagem

Abstract

Hepatitis C virus (HCV) remains an important health care burden worldwide. The genome heterogeneity may be related to the wide variability of clinical and pathological features in HCV-related chronic liver disease. Additionally, knowing the frequency and distribution of the genotypes may enable us to understand the spread of HCV. This study addresses to identify the risk factors for transmission of the hepatitis C, to describe the distribution of the genotypes in a southeast area of Brazil, in patients with chronic hepatitis C, identifying some of the epidemiological and histopathological characteristics of each virus subtype and, to describe the treatment response associated to each genotype. Methods: Genotyping was performed in samples from 136 patients with chronic hepatitis C. The possible routes of contamination and some clinical characteristics were evaluated by a questionnaire. 63 of these patients were submitted to treatment: 41 infected by genotype 1 received peginterferon alfa-2a or alfa-2b plus ribavirin during 48 weeks and 22 received interferon alfa plus ribavirin during 24 weeks (3 infected by genotype 2 and 19 by genotype 3). These patients were followed with samples collection periodically during the treatment and for 24 weeks after the end of therapy to evaluate a sustained virological response. Results: The predominance of HCV genotype 1 (62.5%) was clearly shown, followed by 33.1% for genotype 3 and 4.4% for genotype 2. No difference was observed among the genotypes according to sex, age, frequency of transfusion history prior 1992, alcohol abuse and liver cirrhosis at the diagnosis; a higher number of patients infected by genotype 3 reported a past drug abuse history. Other risk factors were associated with the HCV infection, as the sexual contact with person that had risk comportment and the objects shared by different people. The peginterferon alfa plus ribavirin treatment to the genotype 1 was associated with 61.0% of virological response, and only 31.6% was obtained with interferon alfa indicated to patients infected by genotype 3 (p value = 0,051). This low rate was not associated to previous history of drug use or blood transfusion, length of infection, cirrhosis in the liver biopsy or alcohol previous history. And, the recidive was early in patients that were treated with interferon alfa in comparing with that received peginterferon (log rank – p value = 0,085). Conclusions: The distribution of the HCV genotypes in the evaluated area in Brazil is similar to that in the United States and several European countries. The risk of drug use seems more closely associated with the transmission of genotype 3 when compared to genotype 1. The sexual contact and the objects shared by different people were shown as risk factors to HCV contamination. It was shown the efficacy of peginterferon plus ribavirin to treat patients infected by genotype 1. The rate of sustained virological response with the interferon alfa plus ribavirin therapy to genotype 3 was lower than the showed by the literature (31.6% versus 80.0%).