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Social networks as drivers of syphilis and HIV infection among young men who have sex with men
  1. Kayo Fujimoto1,
  2. Charlene A Flash2,
  3. Lisa M Kuhns3,4,
  4. Ju-Yeong Kim1,
  5. John A Schneider5,6
  1. 1 Center for Health Promotion and Prevention Research, Department of Health Promotion and Behavioral Sciences, Department of Biostatistics and Data Science, School of Public Health, University of Texas Health Science Center at Houston, Houston, TX, US
  2. 2 Division of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
  3. 3 Division of Adolescent Medicine, Ann & Robert H Lurie Children’s Hospital, Chicago, Illinois, USA
  4. 4 Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
  5. 5 Departments of Medicine and Public Health Sciences, University of Chicago, Chicago, IL, USA
  6. 6 Chicago Center for HIV Elimination, University of Chicago, Chicago, IL, USA
  1. Correspondence to Prof. John A Schneider, Departments of Medicine and Public Health Sciences, University of Chicago, 5837 South Maryland Avenue MC 5065, Chicago, IL 60637; jschnei1{at}


Objectives Syphilis and HIV epidemics overlap, yet little is known about combined network and behavioural factors that drive syphilis-HIV coinfection. Our study objective was to assess network contexts and sexual behaviours associated with syphilis-HIV co-infection and monoinfection among a particularly vulnerable subgroup: young Black men who have sex with men (YBMSM). To achieve this objective, we examined factors associated with coinfection by each subgroup as classified by syphilis-HIV infection status: (A) HIV monoinfected, (B) syphilis monoinfected and (C) neither syphilis infected nor HIV infected. In addition, we further identified the factors that are associated with HIV infection or syphilis monoinfection.

Methods Data were collected from a sample of 365 YBMSM, aged 16–29 years, recruited through respondent-driven sampling between 2014 and 2016, in two cities with large HIV epidemics: Houston, TX, and Chicago, IL. We conducted a series of multinomial logistic regression models to predict coinfection, HIV monoinfection and syphilis monoinfection as a function of network and sexual behavioural factors.

Results Coinfection was associated with having network members who are coinfected or HIV infected within one’s social network. Syphilis monoinfection was associated with a higher number of social venues attended, and HIV monoinfection was associated with having more condomless top partners.

Conclusion Public health interventions that address the diagnosis and treatment of syphilis infection and ensure that those with syphilis are being tested for HIV may be promising in limiting the synergy of syphilis-HIV infections in onward transmission. Advancing HIV and syphilis prevention efforts in high-prevalence networks may allow prioritisation of limited resources.

  • HIV
  • syphilis
  • social network analysis
  • sexual risk behavior
  • multinomial logistic regression
  • young Black men who have sex with men (MSM)
  • co-infection

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  • Handling editor Jackie A Cassell

  • Contributors KF conceptualised the study, led the project, designed the network analysis, specified statistical models, conducted the statistical analysis and led the writing of the article. CAF interpreted the results and organised the literature on the topic. LMK designed the data collection, collected the data and interpreted the results. JYK prepared the data, computed the network measures and conducted network analysis. JAS led the project, designed the data collection, collected the data, interpreted the results and conceptualised the study. All authors substantially contributed to the study, engaged in writing and approved the manuscript.

  • Funding This work was supported by the National Institutes of Health (grant numbers 1R01MH100021, 1R01DA039934, K23-MH109358-02 and 1R21GM113694).

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval All three institutions that participated in YMAP (The University of Chicago (UC), Ann & Robert H Lurie Children’s Hospital of Chicago (Lurie) and The University of Texas Health Science Center at Houston School of Public Health (UTHealth)) received approval from the irinstitutional review boards (IRB #HSCSPH120830).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Data will be shared on a requested basis. No additional unpublished data from the study are available.