Skip to main content

A Network Approach to Determine Optimization of PrEP Uptake in Athens, Greece


Although the HIV epidemic in Athens, Greece has reemerged and spread in men who have sex with men (MSM), state-supported PrEP programs have not been instituted. A PrEP intervention was implemented building upon an existing network cohort of MSM (308 participants; 1212 network members). A PrEP intervention cohort of 106 participants was selected based upon sex behaviors. Individual, partner, and network characteristics were compared between the cohorts. The PrEP cohort members were more highly connected and in more influential positions in the network than their peers. Further, their sexual network connections’ behaviors increased their vulnerability to HIV infection relative to the rest of the network’s sex partners. This included greater stimulant use (24.2% vs 7.0%; χ2 = 28.2; p < 0.001), greater rates of at least weekly condomless sex (OR = 2.7; 95% CI 2.1–3.5; χ2 = 59.2; p < 0.001) and at least weekly use of drugs or alcohol during sex (OR = 3.4; 95% CI 2.6–4.3; χ2 = 89.7; p < 0.001). Finally the PrEP cohort’s social networks showed similarly increased vulnerability to seroconversion, including greater rates of injection drug use (4.1% vs 0.5%; χ2 = 3.9; p = 0.04), greater stimulant use (33.6% vs 14.6%; χ2 = 16.9, p < 0.001), and higher rates of recent STIs (21.6% vs 13.1%; χ2 = 4.4; p = 0.04). Thus, this PrEP intervention engaged individuals in vulnerable positions with vulnerable connections within an MSM community.

This is a preview of subscription content, access via your institution.

Fig. 1


  1. Paraskevis D, Nikolopoulos G, Tsiara C, Paraskeva D, Antoniadou A, Lazanas M, et al. HIV-1 outbreak among injecting drug users in Greece, 2011: a preliminary report. Euro Surveill. 2011;16:19962.

    Article  Google Scholar 

  2. Nikolopoulos GK, Chanos S, Tsioptsias E, Hodges-Mameletzis I, Paraskeva D, Dedes N. HIV incidence among men who have sex with men at a community-based facility in Greece. Cent Eur J Public Health. 2019;27:54–7.

    Article  Google Scholar 

  3. Paraskevis D, Nikolopoulos GK, Sypsa V, Psichogiou M, Pantavou K, Kostaki E, et al. Molecular investigation of HIV-1 cross-group transmissions during an outbreak among people who inject drugs (2011–2014) in Athens. Greece Infect Genet Evol. 2018;62:11–6.

    CAS  Article  Google Scholar 

  4. Bozicevic I, Handanagic S, Lepej SZ, Begovac J. The emerging and re-emerging human immunodeficiency virus epidemics in Europe. Clin Microbiol Infect. 2013;19:917–29.

    CAS  Article  Google Scholar 

  5. Nikolopoulos GK, Pavlitina E, Muth SQ, Schneider J, Psichogiou M, Williams LD, et al. A network intervention that locates and intervenes with recently HIV-infected persons: the transmission reduction intervention project (TRIP). Sci Rep Nature Publ Group. 2016;6:1–9.

    Google Scholar 

  6. Tsang MA, Schneider JA, Sypsa V, Schumm P, Nikolopoulos GK, Paraskevis D, et al. Network characteristics of people who inject drugs within a new HIV epidemic following austerity in Athens. Greece J Acquir Immune Defic Syndr. 2015;69:499–508.

    Article  Google Scholar 

  7. Williams LD, Kostaki E-G, Pavlitina E, Paraskevis D, Hatzakis A, Schneider J, et al. Pockets of HIV non-infection within highly-infected risk networks in Athens. Greece Front Microbiol. 2018;9:1825.

    Article  Google Scholar 

  8. Grant RM, Lama JR, Anderson PL, McMahan V, Liu AY, Vargas L, et al. Preexposure Chemoprophylaxis for HIV Prevention in Men Who Have Sex with Men [Internet]. Massachusetts Medical Society; 2010 [cited 2020 Jun 7].

  9. Schueler K, Ferreira M, Nikolopoulos G, Skaathun B, Paraskevis D, Hatzakis A, et al. Pre-exposure prophylaxis (PrEP) awareness and use within high HIV transmission networks. AIDS Behav. 2019;23:1893–903.

    Article  Google Scholar 

  10. Waetjen M, Papadopoulou M, Flores R, Sypsa V, Roussos S, Chanos S, et al. Pre-exposure prophylaxis persistence among Greek sexual minority men: results from PrEP for Greece (P4G) study. AIDS Behav. 2021.

    Article  PubMed  Google Scholar 

  11. Patel P, Borkowf CB, Brooks JT, Lasry A, Lansky A, Mermin J. Estimating per-act HIV transmission risk: a systematic review. AIDS. 2014;28:1509–19.

    Article  Google Scholar 

  12. Papalini C, Lagi F, Schiaroli E, Sterrantino G, Francisci D. Transgender people living with HIV: characteristics and comparison to homosexual and heterosexual cisgender patients in two Italian teaching hospitals. Int J STD AIDS. 2021;32:194–8.

    Article  Google Scholar 

  13. Sarigül F, Sayan M, İnan D, Deveci A, Ceran N, Çelen MK, et al. Current status of HIV/AIDS-syphilis co-infections: a retrospective multicentre study. Cent Eur J Public Health. 2019;27:223–8.

    Article  Google Scholar 

  14. Guerras J-M, Hoyos Miller J, Agustí C, Chanos S, Pichon F, Kuske M, et al. Association of sexualized drug use patterns with HIV/STI transmission risk in an internet sample of men who have sex with men from seven European countries. Arch Sex Behav. 2021;50:461–77.

    Article  Google Scholar 

  15. Bowman B, Psichogiou M, Papadopoulou M, Sypsa V, Khanna A, Paraskevis D, et al. Sexual mixing and HIV transmission potential among Greek men who have sex with men: results from SOPHOCLES. AIDS Behav. 2021;25(6):1935–45.

    Article  Google Scholar 

  16. HIV/AIDS [Internet]. [cited 2020 Jun 3].

  17. Schneider JA, Cornwell B, Ostrow D, Michaels S, Schumm P, Laumann EO, et al. Network mixing and network influences most linked to HIV infection and risk behavior in the HIV epidemic among black men who have sex with men. Am J Public Health. 2013;103:e28-36.

    Article  Google Scholar 

  18. Loutsiou-Ladd A, Panayiotou G, Kokkinos CM. A review of the factorial structure of the brief symptom inventory (BSI): Greek evidence. Int J Test Routledge. 2008;8:90–110.

    Article  Google Scholar 

  19. Smith DK, Pals SL, Herbst JH, Shinde S, Carey JW. Development of a clinical screening index predictive of incident HIV infection among men who have sex with men in the United States. JAIDS Journal of Acquired Immune Deficiency Syndromes. 2012;60:421–7.

    Article  Google Scholar 

  20. Schneider J, Schumm LP, Fraser M, Yeldandi V, Liao C. A gold-standard for entity resolution within sexually transmitted infection networks. Sci Rep. 2018;8:8776.

    Article  Google Scholar 

  21. Morgan E, Skaathun B, Schneider JA. Sexual, social, and genetic network overlap: a socio-molecular approach toward public health intervention of HIV. Am J Public Health. 2018;108:1528–34.

    Article  Google Scholar 

  22. CAHR Poster: HIV Incidence, Momentum Study [Internet]. [cited 2020 Aug 18].

  23. HIV Risk Behaviors: HIV Risk and Prevention Estimates, CDC [Internet]. 2019 [cited 2020 Aug 13].

  24. Pufall EL, Kall M, Shahmanesh M, Nardone A, Gilson R, Delpech V, et al. Sexualized drug use ('chemsex’) and high-risk sexual behaviours in HIV-positive men who have sex with men. HIV Med. 2018;19:261–70.

    CAS  Article  Google Scholar 

  25. Ross EL, Cinti SK, Hutton DW. Implementation and operational research: a cost-effective, clinically actionable strategy for targeting HIV preexposure prophylaxis to high-risk men who have sex with men. J Acquir Immune Defic Syndr. 2016;72:e61-67.

    Article  Google Scholar 

  26. Solomon SS, McFall AM, Lucas GM, Srikrishnan AK, Kumar MS, Anand S, et al. Respondent-driven sampling for identification of HIV- and HCV-infected people who inject drugs and men who have sex with men in India: a cross-sectional, community-based analysis. PLoS Med. 2017;14:e1002460.

    Article  Google Scholar 

  27. Murrill CS, Bingham T, Lauby J, Liu K-L, Wheeler D, Carballo-Diéguez A, et al. Respondent-driven sampling in a multi-site study of black and latino men who have sex with men. J Natl Med Assoc. 2016;108:69–76.

    PubMed  Google Scholar 

  28. Gama A, Martins MO, Dias S. HIV research with men who have sex with men (MSM): advantages and challenges of different methods for most appropriately targeting a key population. AIMS Public Health. 2017;4:221–39.

    Article  Google Scholar 

  29. Borgatti SP, Carley KM, Krackhardt D. On the robustness of centrality measures under conditions of imperfect data. Social Networks. 2006;28:124–36.

    Article  Google Scholar 

  30. Costenbader E, Valente TW. The stability of centrality measures when networks are sampled. Social Networks. 2003;25:283–307.

    Article  Google Scholar 

Download references


This work was supported by Gilead Sciences CO-US-276-1695, R21 AI118998, the Pritzker School of Medicine, and the Hellenic Scientific Society for the Study of AIDS and Sexually Transmitted Diseases. We would like to thank all study participants for the time and effort required to recruit their network members and participate in the interview. We would also like to thank Checkpoint Athens for their facilities and resources utilized in interviews.

Author information

Authors and Affiliations


Corresponding author

Correspondence to John A. Schneider.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Fouché, T., Del Vecchio, N., Papadopoulou, M. et al. A Network Approach to Determine Optimization of PrEP Uptake in Athens, Greece. AIDS Behav 26, 2703–2712 (2022).

Download citation

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • MSM
  • PrEP
  • HIV
  • Athens
  • Greece