The impact of policing and homelessness on violence experienced by women who sell sex in London: a modelling study.

Street-based sex workers experience considerable homelessness, drug use and police enforcement, making them vulnerable to violence from clients and other perpetrators. We used a deterministic compartmental model of street-based sex workers in London to estimate whether displacement by police and unstable housing/homelessness increases client violence. The model was parameterized and calibrated using data from a cohort study of sex workers, to the baseline percentage homeless (64%), experiencing recent client violence (72%), or recent displacement (78%), and the odds ratios of experiencing violence if homeless (1.97, 95% confidence interval 0.88-4.43) or displaced (4.79, 1.99-12.11), or of experiencing displacement if homeless (3.60, 1.59-8.17). Ending homelessness and police displacement reduces violence by 67% (95% credible interval 53-81%). The effects are non-linear; halving the rate of policing or becoming homeless reduces violence by 5.7% (3.5-10.3%) or 6.7% (3.7-10.2%), respectively. Modelled interventions have small impact with violence reducing by: 5.1% (2.1-11.4%) if the rate of becoming housed increases from 1.4 to 3.2 per person-year (Housing First initiative); 3.9% (2.4-6.9%) if the rate of policing reduces by 39% (level if recent increases had not occurred); and 10.2% (5.9-19.6%) in combination. Violence reduces by 26.5% (22.6-28.2%) if half of housed sex workers transition to indoor sex work. If homelessness decreased and policing increased as occurred during the COVID-19 pandemic in 2020, the impact on violence is negligible, decreasing by 0.7% (8.7% decrease-4.1% increase). Increasing housing and reducing policing among street-based sex workers could substantially reduce violence, but large changes are needed.