Molecular epidemiology of a large community-based outbreak of hepatitis B in Bristol, UK

Abstract Background A large outbreak of hepatitis B virus (HBV) infection in the UK occurred between 2001 and 2005 in Bristol, UK. Objectives To identify HBV strains circulating amongst risk groups in the HBV outbreak cohort. Study design Cross-sectional study of acute HBV outbreak cases in Bristol. Results HBV sequences from sera of 95 of the 237 cases (40%) were characterised. The majority of cases (77%) were found to carry an HBV variant belonging to genotype D, designated HBV BV . Eighty-eight percent (36/41) of sequences from injection drug users were HBV BV as were 70% (19/27) from those with heterosexual intercourse as the primary identified risk factor. Of 15 sequences characterised from cases of pre-outbreak acute or chronic hepatitis B residing in Bristol, 40% also carried HBV BV ; the earliest was from a case identified in 1994. Conclusion The findings from this study link the spread of HBV BV from injecting drug users to the general population through heterosexual intercourse during the outbreak. The molecular sequencing of specimens from this outbreak reports the emergence of HBV BV , a HBV strain circulating in Bristol and South West England, as the cause of one of the largest outbreaks of acute hepatitis B in the UK.