Theme: Epidemiology & Public Health Research Year: 2022
Background: People who inject drugs (PWID) are at risk of blood borne virus transmission. We
undertook a global systematic review of injecting prevalence; sociodemographic characteristics of
and risk factors for people who inject drugs (PWID); and HIV, hepatitis C (HCV) and hepatitis B (HBV)
prevalence amongst PWID, updating our 2017 review.
Methods: Consistent with GATHER and PRISMA guidelines, we systematically searched peerreviewed (Medine, Embase, and PsycINFO), internet, and grey literature databases, and
disseminated data requests to international experts and agencies. We searched for data on IDU
prevalence, characteristics of PWID including gender, age, drug use patterns and sociodemographic
and risk characteristics, and prevalence of HIV, HCV and HBV among PWID.
Results: We included all data from the 2017 review and screened an additional 16,712
papers/reports, with data ultimately extracted from 664 eligible papers/reports. Evidence of IDU
was documented in 190 out of 206 countries/territories covering 99% of the population aged 15-64
years, an increase of 11 countries since the 2017 review; IDU prevalence estimates were identified in
102 countries. We estimate that there are 14.7 million (uncertainty intervals (UI) 9.8-21.2 million)
PWID aged 15-64 years globally, with 2.6 million women and 12∙1 million men. Gender composition
varied by location: in North America and Australasia women were estimated to comprise 30∙0% and
34.7% of PWID respectively, compared to 1.7% in South Asia. Globally, we estimate that 16.8% (UI
11.6-22.7%) of PWID are living with HIV; 54.7% (UI 45.2-64.0%) are HCV-antibody positive and 8.5%
(UI 4.8-13.2%) HBsAg-positive, with substantial geographic variation in these levels. There is
substantial exposure to risk among PWID in most countries.
Conclusion: Injecting drug use has been identified in more countries since 2017. Across all countries,
a substantial number of PWID are living with HIV and HCV and are exposed to multiple adverse risk
environments that increase health harms.
Disclosure of interests: In the past three years, LD has received investigator-initiated untied
educational grants for studies of opioid medications in Australia from Indivior and Seqirus. AP has
received investigator-initiated untied educational grants from Seqirus. MF has received investigatorinitiated untied educational grants from Indivior and Seqirus. GD reports grants from Gilead, Abbvie,
Merck, and Bristol-Myers Squibb, personal fees from Gilead, Abbvie, and Merck, and nonfinancial
support from Gilead, Abbvie, and Merck, outside the submitted work. JG is a consultant/advisor and
has received research grants from Abbvie, Cepheid, Gilead Sciences and Merck/MSD. MH reports
honoraria for speaking at meetings from Gilead, Abbvie, and MSD.