HIV preventive interventions, sampling methods and sexual risk behaviour among men who have sex with men

Background: Gay, bisexual and other men who have sex with men (MSM) are at high risk of HIV globally. HIV rates among MSM in Europe show increasing trends, in contrast to declining trends in the general population. During the last five years, an increase in reported HIV cases among foreign-born MSM have been observed in Sweden. Representative data about the MSM population is difficult to collect due to lack of a sampling frame. Respondent driven sampling has been developed to access hidden groups and achieve high response rates. Online sampling methods such as Web-based Respondent driven sampling and stratified sampling in a Web community are new and innovative ways of reaching MSM.

Aims: To systematically gather and review evidence for HIV prevention interventions among men who have sex with men in the European Union/European Economic Area and to test and evaluate different sampling methods to study sexual risk behaviour among Men who have sex with Men.

Methods: A systematic review of HIV preventive interventions among MSM applying the Highest Available Standard of Evidence grading framework was performed to inform European guidelines. Web-based respondent driven sampling was implemented to study sexual risk behaviour and Internet use among MSM. Stratified sampling in a Web community was performed to study HIV testing and prevention uptake among foreign-born MSM living in Sweden. Finally, the samples of MSM in Sweden achieved through Web-based respondent driven sampling, stratified sampling in a Web community, time location sampling and online banner survey sampling, were compared regarding sociodemographics and sexual risk behaviour for HIV.

Results: In total, twenty-four interventions were reviewed and fifteen interventions were graded to be strongly, probably or possibly recommended. Condom use, peer outreach, peerled groups, and universal coverage of antiretroviral treatment were found to be strongly recommended. Web-based respondent driven sampling generated a sample of MSM whom all reported unprotected anal intercourse with at least one casual and one regular sex partner in the past twelve months. Stratified sampling in a Web community produced a sub-sample of foreign-born MSM of which 45% had tested for HIV during the past twelve months. A fifth of participants had never tested. Having talked with a prevention worker in the last year was associated with having tested for HIV in the same time frame. The four different sampling strategies used to study sexual risk behaviour among MSM in Sweden captured participant samples that differed regarding sociodemographic characteristic and reported sexual behaviour.

Conclusions: Condom use, peer outreach, peer-led groups, and universal coverage of antiretroviral treatment are evidence-based corner stones of HIV preventive interventions for MSM. Web-based respondent driven sampling reached MSM engaging in sexual risk behaviour and holds promise for online interventions and referrals to prevention programmes. To achieve higher uptake of HIV testing among foreign-born MSM in Sweden outreach programmes could be scaled up and evaluated. Future studies could benefit from using different sampling methods to achieve comprehensive data and validate findings across samples of MSM.

List of scientific papers

I. Strömdahl S, Hickson F, Pharris A, Sabido M, Baral S, Thorson A. A systematic review of evidence to inform HIV prevention interventions among men who have sex with men in Europe. Eurosurveillance 2015 Apr 16;20(15). pii: 21096
https://doi.org/10.2807/1560-7917.ES2015.20.15.21096

II. Strömdahl S, Lu X, Bengtsson L, Liljeros F, Thorson A. Implementation of Web-Based Respondent Driven Sampling among Men Who Have Sex with Men in Sweden. PLoS One. 2015 Oct 1;10(10):e0138599.
https://doi.org/10.1371/journal.pone.0138599

III. Strömdahl S, Liljeros F, Ekéus Thorson A, Ingemarsdotter Persson K, Forsberg B. HIV Testing and Prevention among Foreign-born Men Who Have Sex with Men: An Online Survey from Sweden. [Manuscript]

IV. Strömdahl S, Ingemarsdotter Persson K, Forsberg B, Berglund T, Kühlmann-Berenzon S, Tikkanen R, Velicko I, Bergström J, Lu X, Bengtsson L, Ekéus Thorson A. Sampling strategies used in Sweden to study sexual risk behaviour for HIV/STI among men who have sex with men: Online banner survey, time location sampling, Web respondent driven sampling and stratified sampling in a Web community. [Manuscript]