HCV genotypes in Sicily: is there any evidence of a shift?

The distribution of HCV strains in any area is characterized by a relative prevalence of one genotype, and a number of less prevalent types. In some Western countries a change from the prevalent HCV genotype 1 to genotypes 3 and 4 has been reported in the last decade. In order to assess possible variations of the distribution of HCV genotypes in Sicily, a southern region of Italy, a hospital-based cohort, collected prospectively, of 3,209 subjects with chronic HCV infection was surveyed, comparing the distribution of HCV genotypes during two consecutive periods, from 1997 to 2002 and from 2003 to 2007, according to age and gender. The results show that genotype 1b, which has been historically the most prevalent in Sicily, is still predominant, followed more distantly by genotypes 2 and 3a. However, a cohort effect for these genotypes was seen when comparing the two time periods. Genotype 1b decreased slowly over the last decade, due to the death of the people infected, leading to a proportional increase of the other genotypes. No evidence was found in support of a major increase in the prevalence of other genotypes, such as genotype 4, in relation to migration patterns.