Evaluation of the scale-up of HIV testing among people who inject drugs in Scotland in the context of an ongoing HIV outbreak

Abstract

Background: A large outbreak of HIV among people who inject drugs (PWID) has been ongoing in Glasgow city centre (GCC), Scotland since early 2015. The outbreak is associated with high levels of homelessness, cocaine injecting and injecting in public places. A key component of the public health response was the scale-up of HIV testing in a range of services engaged with PWID. Our aims were to: 1) evaluate the extent of and change in HIV testing over the course of the outbreak and 2) examine factors associated with reporting an HIV test.

Methods: Self-report of an HIV test in the last 12 months was collected for 15,081 PWID interviewed in six national cross-sectional bio-behavioural surveys during 2008-2018. Multi-variate logistic regression was undertaken to determine trends in HIV testing by region of recruitment (GCC; rest of Glasgow; other Scottish city centres (SCC); and rest of Scotland) and outbreak period (pre: 2008-14; early: 2015-16; ongoing: 2017-18).

Results: HIV testing increased across all regions and was most pronounced in GCC comparing the ongoing (67%) to the pre-outbreak period (33%) (aOR=4.68, 95% CI 3.23 to 6.77, p<0.001). However, compared to other SCCs pre-outbreak (with 46% reporting testing), those recruited in GCC had a lower odds of HIV testing early outbreak (aOR=0.37, 95% CI 0.27 to 0.54, p<0.001) and more modest increased odds in the ongoing outbreak period (aOR=1.41, 95% CI 0.97 to 2.05, p=0.069). Among PWID recruited in the whole of Glasgow in the ongoing phase, reporting an HIV test was associated with injecting cocaine or in public places (aOR=2.20, 95% CI 1.53 to 3.17, p<0.001), receipt of methadone (aOR=1.48, 95% CI 1.01 to 2.17, p=0.042) and incarceration in the last year (aOR=1.72, 95% CI 1.18 to 2.51, p=0.004).

Conclusions: Relatively low levels of HIV testing pre- and early-outbreak likely hindered efforts to control the spread of infection among PWID in Glasgow. Uptake has since increased with expansion of testing across multiple settings, particularly among those at high risk of infection. Further effort is needed to ensure the vast majority of PWID are regularly tested, not just in the epicentre of the outbreak but in other areas with low population prevalence of infection.

Keywords: HIV outbreak; HIV prevention; HIV testing; People who inject drugs; Public health.