Skip to main content

Table 1 Overview of model parameters and processes

From: Potential drivers of HIV acquisition in African-American women related to mass incarceration: an agent-based modelling study

Processes

Description

Demography

 Gender

Seeded at baseline based on gender distribution reported in the 2000 U.S. Census.

 Mortality

Implemented based on HIV disease stage, gender, and use of antiretroviral therapy.

Sexual Behavior and Sexual Network

 Sexual partner preference

Female agents can only partner with male agents and vice versa. Seeded stochastically at baseline based on empirical studies.

 Condom use

Probability of condom use is based on relationship duration (< or ≥ 1 month) and HIV diagnosis status.

Partner acquisition rate

Agents assigned a personal annual mean number of partners, which is allowed to vary stochastically year-to-year.

 Sex frequency

Agents stochastically assigned a desired number of sex acts per partner per year. At the partnership level the resulting number of sex acts represents a compromise between the two partners.

Relationship length

Varies stochastically based on empirical data on mean and median relationship lengths. Agents have a 50% likelihood of relationship dissolution during incarceration.

Incarceration

 Incarceration rate

Derived from 2005 data from the Philadelphia Commission on Sentencing for African American men, held constant through model run. Varied by type of correctional facility (jail vs. prison) and recidivism status (prior offense vs. first offence).

 Sentence length

Derived from 2005 data from the Philadelphia Commission on Sentencing for African American men, held constant through model run. Varied by type of correctional facility (jail vs. prison).

HIV/AIDS

 Initial HIV prevalence

Based on HIV surveillance data for African American men and women in Philadelphia.

Testing

Agents test stochastically throughout the year with differing probabilities based on gender. Diagnosed agents are less likely to transmit to HIV-negative partners.

Viral suppression

Only HIV-diagnosed agents are eligible for viral suppression. Virally suppressed agents are less likely to transmit to HIV-negative partners.

HAART discontinuation

Only HIV-diagnosed agents are eligible to initiate and discontinue HAART. Annual probability of discontinuation differs by gender and incarceration status.

Transmissibility

Based on STI status, HIV diagnosis status, HAART adherence, and disease stage.

  1. Abbreviations: HAART highly active antiretroviral therapy, STI sexually transmitted infection
  2. Bolded parameters are those impacted by incarceration or partner incarceration in order to simulate a “high-risk” period