Cocaine injecting and homelessness linked to Glasgow HIV outbreak

03 May 2019

Rising HIV infections among people who inject drugs in Glasgow reveals changes in injecting behaviours, with cocaine injecting becoming more common – a practice with greater HIV risks

A person sleeping rough in the street in a sleeping bag.

Cocaine injecting and homelessness are two of the biggest contributors to rising HIV infections among people who inject drugs in Glasgow, reveals a new epidemiological analysis.

In 2015, an outbreak of HIV among people who inject drugs in the Greater Glasgow and Clyde (GGC) area of Scotland was identified despite a 30-year, high-coverage harm reduction programme that distributes around 1 million new needles and syringes each year. Three years later, the epidemic persists – but which groups are falling through the cracks?

In an attempt to understand the re-emergence of HIV in this group – where until recently incidence had remained low since the first outbreak in the early 1980s – the investigators analysed bio-behavioural surveillance data from the participants of four Needle Exchange Surveillance Initiative (NESI) surveys completed during 2011–18. Trained interviewers asked participants questions about their demographics, behaviours, and service use, and they were asked to give dried blood spots to be tested anonymously for hepatitis C and HIV.

The investigators then ran several models to determine individual and environmental risk factors associated with HIV infection. The analysis revealed that between 2011 and 2018, HIV prevalence in the survey respondents rose from 0.1% to 4.8% in Greater Glasgow and Clyde, and from 1.1% to 10.8% in Glasgow city centre. Over this same period, prevalence of cocaine injecting rose from 16% to 50% in the sample overall, and from 37% to 77% in Glasgow city centre.

Those who were HIV-positive were more likely to have been homeless in the past six months, been in prison at least five times since they first started injecting, and injected cocaine in the last six months. After accounting for environmental and individual risk factors, HIV infection was associated with cocaine injecting and homelessness.

This study provides additional evidence of the poor health outcomes and inequalities experienced by homeless populations, and highlights the need for more research around motivations and patterns of stimulant injecting in this group to inform policy and practice responses.

Homeless populations were more likely to inject cocaine despite heroin being the long-standing dominant illegal substance. Interestingly, this study provides new evidence that links powder cocaine injecting to homelessness, alongside studies elsewhere reporting increasing rates of crack-cocaine injecting among homeless populations.

This shift in substance use is not unique to Glasgow; across Europe, HIV outbreaks in Luxembourg, Athens and Budapest have occurred despite robust harm reduction programmes. Many point to the availability of high-quality cocaine on the market as the reason why people are shifting away from heroin.

In this research, cocaine injecting was also significantly associated with HIV after controlling for injecting frequency and unprotected sex. When compared to heroin, cocaine has a smaller half-life (the duration of a drugs action) so is associated with more frequent injecting. Cocaine is also more likely to be taken in social scenarios which can lead to increased HIV risk-taking behaviours.

The authors note, “This result suggests that there might be other unmeasured aspects of cocaine injecting that heighten the risk of HIV infection among PWID in Glasgow. Further research on the role of cocaine injecting in facilitating and sustaining rapid transmission of HIV among PWID is merited.”

In a linked article, Vana Sypa, Assistant Professor of Epidemiology and Preventative Medicine at the University of Athens, underlined how vulnerable populations of people who inject drugs are to economic, social, and drug-market scene changes and how fragile the success of interventions can be in preventing HIV outbreaks: “High-coverage harm reduction programmes should be combined with surveillance of HIV infection and associated behaviours through community-based programmes, with an effort to reach the most underserved populations and to react rapidly to potential threats.”

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Rising HIV infections among people who inject drugs in Glasgow reveals changes in injecting behaviours, with cocaine injecting becoming more common – a practice with greater HIV risks
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Written by Caitlin Mahon

Content Specialist - HIV & Sexual Health