Prevention of HIV infection for people who inject drugs:

Why individual, structural and combination approaches are

neededLouisa Degenhardt1, Bradley Mathers1, Peter Vickerman2,

Tim Rhodes3, Carl Latkin4and Matt Hickman5

1. National Drug and Alcohol Research Centre, University of NSW, Australia2. London School of Hygiene and Tropical Medicine, UK3. Centre for Research on Drugs and Health Behaviour, LSHTM, UK4. Johns Hopkins Bloomberg School of Public Health, USA

5. University of Bristol, UK

Interventions for preventionmechanism of effect

Preventing HIV transmission among people who inject drugs: multiple mechanisms

Prevention of injecting related transmission: reduce injecting frequency

reduce unsafe injecting events

reduce HIV infectivity

Sexual transmission:reduce unsafe sexual events

reduce HIV infectivity

Interventions for preventionevidence of impact

Inject. frequency

Injecting risks

Sex risks HIV infectivity

HIV incidence

HIV testing -- ↓ ↓ -- --Individual interventions for HIV risk ↓ ↓ ↓ -- --Network/peer interventions for HIV risk ↓ ↓ ↓ -- --Needle syringe programs (NSP) ↓ -- -- ↓Condom provision -- -- ↓ -- ↓Opioid substitution therapy (OST) ↓ ↓ -- ↓Naltrexone – Oral -- -- --Naltrexone – Implant ↓ ↓ -- -- --Pharmacotherapy for stimulant dependence -- --CBT for stimulant dependence ↓ -- -- -- --STI treatment -- -- -- -- ↓Antiretroviral treatment (ART) -- -- -- ↓ ↓Safe injecting centres (SICs) ↓ -- -- --Compulsory detention of drug users -- ↑ ↑ -- --

Modelling impactvarying coverage and combinations

Modelling different levels of intervention coverage and combination

• Extended an existing deterministic model developed by Vickerman et al

• Epidemiological parameters and effect sizes used were based on observed data:• Injecting HIV epidemics• Frequency of risk behaviours• Impact of OST, NSP and ART on HIV transmission• Service coverage levels

Effects of recruitment rates and intervention combinations on HIV incidence after 5 years

OST and NSP only, 50% recruitment annually: 9-37% reduction in HIV incidence

ART onlyCD4 <200

OST + NSPonly

ART only,CD4 <350

OST + NSP + ART

Effects of recruitment rates and intervention combinations on HIV incidence after 5 years

ART onlyCD4 <200

OST + NSPonly

ART only,CD4 <350

OST + NSP + ART

ART to CD4<200 only, 50% recruitment annually: 5-17% reduction in HIV incidence

Effects of recruitment rates and intervention combinations on HIV incidence after 5 years

ART onlyCD4 <200

OST + NSPonly

ART only,CD4 <350

OST + NSP + ART

ART to CD4<350 only, 50% recruitment annually: 9-34% reduction in HIV incidence

Effects of recruitment rates and intervention combinations on HIV incidence after 5 years

ART onlyCD4 <200

OST + NSPonly

ART only,CD4 <350

OST + NSP + ART

OST+NSP+ART<350, 50% recruitment annually: 18-63% reduction in HIV incidence

Current coverageOST, NSP and ART

© Reference Group to the United Nations on HIV and Injecting Drug Use 2010

Global estimate of the number of IDUs:15.9million (11.0-21.2 million)

Reports of injecting drug use in 151 countries

Needles-syringes distributed, per IDU, per year

less than 100

100 – 200

greater than 200 NSP present but program data not available

No IDU reportedNo NSP

Needles-syringes distributed, per IDU, per year

Globally, overall, only 22 needles-syringes (range 12-42) are distributed per IDU per year

Opioid substitution therapy (OST)

Present in 75 countries Absent in 76 countries where injecting occurs

Number of OST recipients for every 100 IDUs

Globally, overall, only 8 people on OST (range 6-12) for every 100 IDUs

Number of IDUs on ART per 100 HIV+ IDUs

less than 25

25 – 75

greater than 75 IDU present but ART program data not available

No IDU reportedNo OST

Number of IDUs on ART per 100 HIV+ IDUs

Globally, overall, only 4 IDUs on ART (range 2-18) for every 100 HIV+ IDUs

Improving coveragesocial and structural interventions

Policy and environmental factors influence accessibility, coverage and quality of services

It necessary to address these structural barriers

For example: • Creating safer injecting environments; • Reforming laws prohibiting treatments; • Reducing the harms of policing

Improving coverage and impact of prevention interventions

In summary:• High coverage of ART and OST and NSP can reduce HIV

incidence in IDUs by more than 50%Short-term, small-scale interventions unlikely to impact

• Current coverage is vastly inadequate few countries have high coverage of any intervention -

very few have high coverage of all three

• Structural factors limiting impact and needed when environmental factors limit scale-up

•We know enough to act now But the evidence base must continue to improve so we can continue to improve the response: surveillance, monitoring and evaluation, efficacy and (cost) effectiveness

Acknowledgments

Chiara Bucello, Mary Kumvaj, Erol Digiusto, Tomas Zabransky, Mauro Guarinieri, Mukta Sharma, Maria Prins,Judy Auerbach, Francisco Bastos, and Don Des Jarlais

The Lancet Special Series gurus: Chris Beyrer, Steffanie Strathdee, Adeeba Kamarulzaman, Kasia Malinowska-Sempruch

The Lancet Editors: Pamela Das and Richard Horton