Increasing risk behavior can outweigh the benefits of anti-retroviral drug treatment on the HIV incidence among men-having-sex-with-men in Amsterdam

TL;DR

This study uses a complex agent-based model to show that increased risk behavior among MSM can negate the benefits of antiretroviral therapy, emphasizing the importance of reducing risky behaviors to control HIV spread.

Contribution

The paper introduces a validated agent network model that predicts HIV incidence among MSM, highlighting the impact of risk behavior increases on therapy effectiveness.

Findings

HIV incidence can increase despite effective therapy if risk behavior rises by 30%.

Model accurately reproduces historical HIV incidence data in Amsterdam.

Reducing risk behavior is crucial for controlling HIV spread even with advanced treatments.

Abstract

The transmission through contacts among MSM (men who have sex with men) is one of the dominating contributors to HIV prevalence in industrialized countries. In Amsterdam, the capital of the Netherlands, the MSM risk group has been traced for decades. This has motivated studies which provide detailed information about MSM's risk behavior statistically, psychologically and sociologically. Despite the era of potent antiretroviral therapy, the incidence of HIV among MSM increases. In the long term the contradictory effects of risk behavior and effective therapy are still poorly understood. Using a previously presented Complex Agent Network model, we describe steady and casual partnerships to predict the HIV spreading among MSM. Behavior-related parameters and values, inferred from studies on Amsterdam MSM, are fed into the model; we validate the model using historical yearly incidence data. Subsequently, we study scenarios to assess the contradictory effects of risk behavior and effective therapy, by varying corresponding values of parameters. Finally, we conduct quantitative analysis based on the resulting incidence data. The simulated incidence reproduces the ACS historical incidence well and helps to predict the HIV epidemic among MSM in Amsterdam. Our results show that in the long run the positive influence of effective therapy can be outweighed by an increase in risk behavior of at least 30% for MSM. Conclusion: We recommend, based on the model predictions, that lowering risk behavior is the prominent control mechanism of HIV incidence even in the presence of effective therapy.