Hepatitis C virus genotypes distribution and transmission risk factors in Luxembourg from 1991 to 2006

Aim: To analyze the Hepatitis C virus (HCV) genotype distribution and transmission risk factors in a population of unselected patients in Luxembourg. Methods: Epidemiological information (gender, age and transmission risks) were collected from 802 patients newly diagnosed for hepatitis C and living in Luxembourg, among whom 228 patients referred from prison. Genotyping using 5′noncoding (5′NC) sequencing was performed. We compared categorical data using the Fisher's exact F-test and odds ratios (OR) were calculated for evaluating association of HCV genotype and risk factors. Results: The sex ratio was predominantly male (2.2) and individuals aged less than 40 years represented 49.6% of the population. Genotype 1 was predominant (53.4%) followed by genotype 3 (33%). Among risk factors, intravenous drug usage (IVDU) was the most frequently reported (71.4%) followed by medical-related transmission (17.6%) including haemophilia, transfusion recipients and other nosocomial reasons. Genotype 3 was significantly associated to IVDU (OR = 4.84, P < 0.0001) whereas genotype 1 was significantly associated with a medical procedure (OR = 2.42, P < 0.001). The HCV genotype distribution from inmate patients differed significantly from the rest of the population (Chi-square test with four degrees of freedom, P < 0.0001) with a higher frequency of genotype 3 (46.5% vs 27.5%) and a lower frequency of genotype 1 and 4 (44.7% vs 56.8% and 5.3% vs 9.6%, respectively). IVDU was nearly exclusively reported as a risk factor in prison. Conclusion: We report the first description of the HCV genotype distribution in Luxembourg. The repartition is similar to other European countries, with one of the highest European prevalence rates of genotype 3 (33%). Since serology screening became available in 1991, IVDU remains the most common way of HCV transmission in Luxembourg.