Displacement of sexual partnerships in trials of sexual behavior interventions: A model-based assessment of consequences

Abstract

We investigated the impact of the displacement of sexual activity from adherent recipients of an intervention to others within or outside a trial population on the results from hypothetical trials of different sexual behavior interventions. A short-term model of HIV-prevention interventions that lead to female rejection of male partnership requests showed the impact of displacement expected at the start of a trial. An agent-based model, with sexual mixing and other South African specific demographics, evaluated consequences of displacement for sexual behavior interventions targeting young females in South Africa. This model measured the cumulative incidence among adherent, non-adherent, control and non-enrolled females in a hypothetical trial of HIV prevention. When males made more than one attempt to seek a partnership, interventions reduced short-term HIV infection risk among adherent females, but increased it among non-adherent females as well as controls, non-enrolled (females eligible for the trial but not chosen to participate) and ineligible females (females that did not qualify for the trial due to age). The impact of displacement depends on the intervention and the adherence. In both models, the risk to individuals who are not members of the adherent intervention group will increase with displacement leading to a biased calculation for the effect estimates for the trial. Likewise, intent-to-treat effect estimates become nonlinear functions of the proportion adherent.

Calibration and Validation of the Colorectal Cancer and Adenoma Incidence and Mortality (CRC-AIM) Microsimulation Model Using Deep Neural Networks

“…We note that meta-models and emulators have also been used in simulation models for purposes other than calibration, such as conducting costeffectiveness and value-of-information analyses or developing online decision support tools. 78,79 Another class of search strategies for calibration involves statistical and sampling methods, 63 which includes Bayesian calibration with several variations such as Bayesian melding, 80 Sampling Importance Resampling, Rejection Approximate Bayesian Computation (ABC), and Incremental Mixture Importance Sampling (IMIS). 81 Volpatto et al 9 and Wade et al 82 used Bayesian calibration with Cascading Adaptive Transitional Metropolis in Parallel (CATMIP) 83 for parallel sampling.…”

“…Another class of search strategies for calibration involves statistical and sampling methods, 63 which includes Bayesian calibration with several variations such as Bayesian melding, 80 Sampling Importance Resampling, Rejection Approximate Bayesian Computation (ABC), and Incremental Mixture Importance Sampling (IMIS). 81 Volpatto et al 9 and Wade et al 82 used Bayesian calibration with Cascading Adaptive Transitional Metropolis in Parallel (CATMIP) 83 for parallel sampling.…”

Simulations for designing and interpreting intervention trials in infectious diseases

“…Simulations can also help predict potentially harmful indirect effects. In an intervention where women are encouraged to refuse sexual acts with men, other women in the population, either study participants or nonparticipants might be sought out by the men refused by women in the trial; these are known as spillover effects [ 4 ] or displacement [ 11 ]. If displacement occurs, the incidence of HIV may be higher in the women not benefitting from the intervention than it would have been if the trial had not occurred.…”

Simulations for Designing and Interpreting Intervention Trials in Infectious Diseases

“…Simulations can also help predict potentially harmful indirect effects. In an intervention where women are encouraged to refuse sexual acts with men, other women in the population, either study participants or nonparticipants, might be sought out by the men refused by women in the trial, known as spillover effects [4] or displacement [11]. If displacement occurs, the incidence of HIV may be higher in the women not benefitting from the intervention than it would have been if the trial had not occurred.…”