Age trend in hepatitis C virus genotype distribution as seen in a Brussels teaching hospital

The hepatitis C virus genotype distribution was studied among age groups in 501 referred patients with chronic hepatitis C by INNO-LiPA HCV II (Innogenetics, Belgium). Ten patients had coinfection with several genotypes. Two hundred seventy of 491 singly infected individuals (57%) had lb, 66 (13.4%) 3a, 57 (11.6%) la. HCV subtype lb was predominant but its prevalence increased with age (76.5% of patients born in the '20s, 39.3% in the '70s) (P <0.0001). Three possibilities could explain the shift towards a wider variety of genotypes in younger age. (1) lb could be the original subtype in this population, (2) the non-lb subtypes could give less chronic carriers, (3) the non-1b subtypes could have a higher mortality, which seems improbable. The lb genotype seems the oldest subtype in our country while others were imported later through increased population movements and changing habits.