5. Updated global estimates of prevalence of People Who Inject Drugs and coverage of harm reduction – what has changed between 2017 and 2021

In 2017 we estimated that there were 15.6 million PWID globally. The 2017 review found evidence of injecting from 179 countries (99% of global population) and an extra 29 countries than the previous 2007 estimate. In the latest 2022 global – presented at Lisbon Addictions – we found conflicting evidence on prevalence of PWID in some countries.

Comparison of 2021 and 2017 global estimates of PWID prevalence by method of prevalence estimation. Simulation modelling excluding prevalence estimates using less robust methods of estimation (e.g. relying upon population survey or hotspot mapping – compared to other indirect estimation techniques.

We will present detailed examination of conflicting estimates from 2017 and 2022 global review for specific countries in Europe and elsewhere. We will present findings from simulation studies that removes prevalence estimates using less robust methods.

The 2022 Global review found more estimates of PWID than the previous 2017 review – but also found some conflicting evidence. The assessment of research method quality of prevalence estimation methods may need to be revised. European and Global bodies need to encourage countries to invest in better methods of estimating PWID prevalence.