Re-emergence of injecting drug use-related HIV despite a comprehensive harm reduction environment

Background

In 2015, an outbreak of Human Immunodeficiency Virus (HIV) was identified among people who inject drugs (PWID) in the Greater Glasgow and Clyde (GGC) area of Scotland, an area which distributes over one million needles and syringes per year. This is the largest such incident in the UK for 30 years. This study provides the first epidemiological analysis of the impact of the outbreak on HIV prevalence trends in the population and the individual and environmental risk factors associated with infection.

Methods

Four cross-sectional anonymous bio-behavioural surveys of almost 4000 PWID attending services providing injecting equipment across GGC between 2011 and 2018 were analysed. Logistic regression was used to determine factors associated with HIV infection, as determined through dried blood spot testing.

Results

Between 2011-12 and 2017-18, HIV prevalence in GGC rose from 0·1% (1/927) to 4·8% (39/821) overall, and from 1·1% (1/87) to 10·8% (25/231) in Glasgow city centre, respectively. Over the same period, the prevalence of cocaine injecting in GGC rose from 16% (129/806) to 50% (291/583) overall, and from 37% (26/70) to 77% (117/153) in Glasgow city centre. HIV infection was more likely among PWID who had: participated in 2015-18 versus earlier survey years (AOR 3.4, 95% CI: 2·0 to 9·6); been homeless in the past six months versus not homeless in the past six months (AOR 3·0, 95% CI: 1·7 to 5·0); multiple incarcerations since first began injecting versus low number of incarcerations (AOR 2·1, 95% CI: 1·2 to 3·7); and injected cocaine within the past six months versus not injected cocaine in the past six months (AOR 6·7, 95% CI: 3·8 to 12·1). Age per one-year of increase was also a significant factor (AOR 1·1, 95% CI: 1·0 to 1·1). Gender showed borderline significance with females more likely to be HIV positive than males (AOR 1·7, 95% CI: 0·9 to 3·2).

Conclusions

Despite high coverage of harm reduction interventions, Glasgow has experienced a rapid rise in prevalence of HIV among its PWID population, associated with homelessness, incarceration and a major shift to injection of cocaine. Robust surveillance through regular HIV testing of high risk populations is critical to ensure outbreaks are detected and rapid responses are informed by the best available evidence.