# Mitigating HIV risk associated with widow cleansing and wife inheritance using combined biomedical and structural interventions in western Kenya: a mathematical modeling study

## TL;DR

This study models how combining biomedical and structural interventions can reduce HIV risk for women in western Kenya who undergo widow cleansing and wife inheritance practices.

## Contribution

The study introduces a mathematical model integrating biomedical and structural interventions to mitigate HIV transmission linked to widow cleansing and wife inheritance.

## Key findings

- Combined biomedical and structural interventions could avert up to 16.1% of HIV infections among widowed women with high uptake.
- Biomedical interventions alone averted 2.6% of infections with high uptake, but had smaller impacts on men.
- Modeled HIV prevalence among inherited widows matched observed data at 59.8%.

## Abstract

In parts of Africa, women who become widowed lose housing, bank accounts, and other property and must re-marry to avoid extreme poverty. To re-marry, some women are required to undergo widow “cleansing”—condomless sex with a man who removes “impurities” ascribed to her from her husband’s death—and are “inherited” as a wife of a brother-in-law. This study explores how HIV biomedical and structural interventions could reduce HIV-related harms associated with these practices.

We adapted EMOD-HIV, an HIV agent-based network transmission model previously calibrated and validated for the Nyanza region of western Kenya. Building on the model’s pre-existing configuration of marriages, mortality, and widowhood, we added widow cleansing and wife inheritance with assumptions based on literature. Modeled HIV prevalence among inherited widows was validated to match observed data. We modeled the effect of widowed women, cleansers, and inheritors receiving biomedical HIV interventions (testing, treatment for those tested positive, and 1 year of pre-exposure prophylaxis (PrEP) initiated at cleansing for those tested negative) with or without structural interventions (female empowerment). We modeled low (30%) and high (70%) intervention uptake and reported HIV outcomes including cumulative infections over 2025–2050.

Modeled HIV prevalence among inherited widowed women was 59.8% (95% CI: 59.5–60.2%), comparable to observed prevalence of 64.1% (95% CI: 63.2–65.4%). Among all widowed women, biomedical interventions averted 2.0% (95% CI: 1.3–2.6%) of HIV infections with low uptake and 2.6% (95% CI: 2.0–3.2%) with high uptake. Combined biomedical and structural interventions averted 7.8% (95% CI: 7.2–8.4%) of HIV infections with low uptake and 16.1% (95% CI: 15.5–16.6%) with high uptake. Impacts were smaller for men, e.g., high-uptake structural and biomedical interventions averted 1.8% (95% CI: 1.5–2.2%) of infections among cleansers and 2.7% (95% CI: 2.4–3.0%) among inheritors.

Widowed women are a vulnerable population with extremely high HIV prevalence. Combined biomedical and structural interventions focused on the practice of widow cleansing and wife inheritance have the potential to avert up to one-quarter of HIV infections among widowed women, and a smaller proportion among men participating in these practices.

The online version contains supplementary material available at 10.1186/s12916-025-03906-5.