HCV genotypes in western Sicily: any evidence for a shift?

Abstract

Background: The relative prevalence of each HCV strain in a specific country is characterized by a predominant genotype and a number of other sub-prevalent types. Over the last decade a shift away from the prevalent HCV G1 towards G3 and G4 has been reported in some countries, and might affect the global management of HCV disease. Aim: In order to assess any possible variation in the prevalence of HCV genotypes in Sicily, we surveyed an hospital based cohort of subjects with chronic HCV infection observed over the last ten years. Patient and methods: 3209 Italian patients resident in Western Sicily, 1842/1367 M/F, between 1 and 89 years of age, presented at our tertiary referral Laboratory between 1997 to 2007 and genotyped by Line Probe Assay (INNOLIPA HCV III). We compared the distribution of the HCV genotypes in two consecutive periods, from 1997 to 2002 and from 2003 to 2007, according to age. Results and conclusion: The prevalent genotypes was 1 in all age groups, but the rate of subtype 1b decrease between 1997 and 2007 from 80.7 to 63.0% with a proportional low increase of the other genotypes. In the first period genotype 1 and 2 were more prevalent in the persons aged 46-65 years but in the second period the rates were very high in the elderly (>56 years), suggesting a cohort effect. Genotype 3a was more frequent among younger people (<35 years) and we observed a 10% increase of this genotype in the subject younger than 25 years and in the subject aged 46-55 years among the two period. Genotype 4 was the most constant in the time but increase in the last period in the subject aged 36-45 years from 1.8 to 9.1% and genotype 5 was found only in two patients.