Molecular epidemiology of newly acquired hepatitis C infections in England 2008-2011: genotype, phylogeny and mutation analysis

Analysis of laboratory testing data collected through the Sentinel Surveillance programme has provided a method for identifying individuals who have recently acquired their hepatitis C virus (HCV) infection. Access to samples from these individuals provided a rare opportunity to undertake molecular characterization studies.

To describe the epidemiology and genetic diversity of hepatitis C in recent seroconverter infections and to predict how this will impact on HCV treatment and control.

One hundred and forty seven samples were available from individuals, identified to have recently acquired their HCV infection. Genotype determination with additional phylogenetic analysis was carried out on NS5B sequences. Analysis across the NS3 region investigated the presence of antiviral resistance mutations. Where possible, molecular data was linked to demographic and risk/behavioural factor information.

The majority of new infections occurred in males with a mean age of 37 years. The most commonly observed genotypes were 1a (49%) and 3a (42%) and injecting drug use (58%) was the most common risk factor. Genotype distribution differed between persons who inject drugs and those with other risk factors suggesting two possible epidemics. Phylogenetic analysis indicated possible transmission networks within specific risk groups. Amino acid changes associated with antiviral resistance were noted in the NS3 region in some samples.

Continued surveillance of linked molecular, virological, demographic and epidemiological information on recently acquired infections will contribute to understanding the on-going HCV epidemic in England.