Modeling the impact of interventions during an outbreak of HIV infection among people who inject drugs in 2012-2013 in Athens, Greece

Eleni Flountzi, Aaron G Lim, Peter T Vickerman, Dimitrios Paraskevis, Mina Psichogiou, Angelos Hatzakis, Vana Sypsa*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

3 Citations (Scopus)
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A large HIV outbreak in People Who Inject Drugs (PWID) occurred in Athens, Greece in 2011-2013. In response, opioid substitution treatment (OST) and needle and syringe programs (NSP) were scaled-up and a seek-test-treat program was implemented. We aim to assess the impact of these interventions.

A mathematical model of HIV transmission among PWID was calibrated to data available over time (2009-2013) on HIV prevalence, NSP/antiretroviral treatment (ART) coverage and high-risk injection. A combined interventions scenario, including decrease in high-risk injection through linkage to OST and modification of risk behaviours and access to NSP and ART, was compared to a counterfactual scenario (no improvement at the levels of these interventions), with HIV incidence being the main outcome.

HIV incidence increased from <0.1 new cases/100 person-years in 2009 to 11.0 (95% CrI: 6.8,16.1) in 2012. Under both models, a subsequent decline was projected following early 2012, with incidence at the end of 2013 in the combined interventions scenario being lower by 77% compared to the counterfactual. The projected reduction in incidence under the intervention scenario was in agreement with empirical data. HIV prevalence would have
escalated to 20.4% (95%CrI:16.9%,23.6%) in 2013 under the counterfactual scenario (vs. 16.8% (95%CrI:11.2%,23.0%) under the combined interventions scenario). In total, 31.4% of HIV cases (392) were averted over 2012-2013.

These results underline the importance of high-coverage harm reduction programs and of community-based interventions to rapidly reach PWID most in need.
Original languageEnglish
Article number109396
Number of pages29
JournalDrug and Alcohol Dependence
Early online date5 Mar 2022
Publication statusPublished - 26 Mar 2022

Bibliographical note

Funding Information:
ARISTOTLE program work was supported by the National Strategic Reference Framework 2007–2013 ( MIS 365008 ) and co-funded by the European Social Fund and national resources. Additional financial support for ARISTOTLE was provided by the Hellenic Scientific Society for the study of AIDS and STDs and the project "Preventing HIV Transmission by Recently-Infected Drug Users" (NIH National Institute of Drug Abuse Grant DP1 DA034989).

Funding Information:
The authors would like to thank ARISTOTLE participants and staff. AGL and PV acknowledge support from the National Institute for Health Research (NIHR) Health Protection Research Unit (HPRU) in Behavioural Science and Evaluation at the University of Bristol.

Publisher Copyright:
© 2022 Elsevier B.V.


  • PWID
  • HIV
  • outbreak
  • harm reduction
  • modeling


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