Sexually transmitted infections simulator (STIsim)

Overview

STIsim is an agent-based modeling framework for simulating co-circulating sexually transmitted infections. Built on the Starsim architecture, it supports structured sexual networks, multiple co-transmitting STIs (HIV, syphilis, chlamydia, gonorrhoea, trichomoniasis, BV, and others), risk-stratified populations, and a flexible intervention library covering screening, testing, treatment, and prevention. STIsim is implemented in pure Python (with an R interface via rstarsim), is extensively tested and documented, and runs in seconds to minutes on a laptop.

Installation

STIsim is most easily installed via PyPI:

pip install stisim

Example models

End-to-end country analyses built with STIsim are good starting points for understanding how to set up, calibrate, and run real-world models:

  • syph_dx_zim — Analysis of novel syphilis diagnostics in Zimbabwe.
  • stisim_vddx_zim — Analysis of novel point-of-care diagnostics for vaginal discharge syndrome in Zimbabwe.

Publications

Publications using STIsim include:

  1. Reduction in overtreatment of gonorrhoea and chlamydia through point-of-care testing compared with syndromic management for vaginal discharge: a modelling study for Zimbabwe (2026). Stuart RM, Newman LM, Manguro G, Dziva Chikwari C, Marks M, Peters RPH, Klein D, Snyder L, Kerr C, Rao DW. Sexually Transmitted Infections. https://doi.org/10.1136/sextrans-2025-056646

  2. Point-of-care testing to strengthen sexually transmitted infection case management in resource-constrained settings (2026). Peters RPH, Manguro G, Ong’wen PA, Mdingi MM, Applegate TL, Stuart R, Harding-Esch EM, Manabe YC, Ndowa F, Van Der Pol B. Sexually Transmitted Infections. https://doi.org/10.1136/sextrans-2025-056833

  3. Estimating the value of novel tests for active syphilis in Zimbabwe: how much overtreatment can be avoided? (2026). Stuart RM, Marks M, Dziva Chikwari C, Muellenmeister AM, Abeysuriya RG, Manguro G, Peters RPH, Rao DW, Newman LM. Sexually Transmitted Diseases (forthcoming).

Roadmap

The development roadmap is maintained on GitHub Projects.

Contact

If you have questions or would like to collaborate, please get in touch.

Email Us