An outbreak of HIV and hepatitis C infection in young people who inject drugs in Belfast due to cocaine injecting.

Author: Sarah Arnold, Eimhear Rainey, Gillian Armstrong, Bronagh Clarke, Diarmuid O'Donovan, Annelies McCurley, Ruth Campbell, Joy Murphy, Tamyo Mbisa, David Bibby, Daniel Bradshaw, Derek Fairley, Daniel Bradshaw, Bronagh McBrien

Theme: Epidemiology & Public Health Research Year: 2023

Northern Ireland has traditionally had a very low prevalence of HIV and hepatitis C (HCV) infections in people who inject drugs (PWIDs). All HCV infections are sequenced, and in July 2020 a cluster of 1a HCV infections was detected on phylogenetic analysis. An outbreak of HCV was declared, and a multi-agency approach taken to tackling the outbreak.

Case finding for HCV, HIV and hepatitis B (HBV) was performed via contact tracing and testing, whole hostel testing, and outreach testing of PWID. Descriptive epidemiology was conducted on the enhanced surveillance data, and included analysis of age, sex, postcode, and risk factors. The Unlinked Anonymous Monitoring (UAM) Survey results were analysed to look for changes in risk behaviour.
Confirmed cases were defined as new diagnoses of HCV and/or HIV which were part of the phylogenetic cluster from 1 January 2017.

To date, 158 confirmed cases of 1a HCV and 16 cases of HIV have been detected centred in Belfast. Two thirds of the cases of HCV were males, with median age 30, compared to half of the HIV cases, with a median age of 27 years. The most common risk factors for HCV were PWID (151, 96%), homelessness (81, 51%), and prison (91, 58%); with one third of cases experiencing all three (56, 35%). UAM demonstrated an increase in cocaine injecting, frequency of injecting and groin injecting, but no increase in usage of needle and syringe exchange (NSES).

This outbreak of HIV and HCV in a young cohort in Belfast is associated with cocaine injecting. This has led to enhanced NSES provision in Belfast, and increased testing of the at-risk population across the country.

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