Impact of Public Safety Policies on HIV Transmission Dynamics in Tijuana, Mexico

Abstract

Background

North Tijuana, Mexico, along the US border, is home to many individuals at high-risk for transmitting and acquiring HIV. Recently, policy shifts by local government impacted how these individuals were handled by authorities. Here we examined how this affected regional HIV transmission dynamics.

Methods

HIV pol sequences and associated demographic information were collected from eight research studies enrolling persons in Tijuana, and were used to infer viral transmission patterns and transmission clusters. To evaluate the impact of recent policy changes on HIV transmission dynamics, qualitative interviews were performed on a subset of recently infected individuals.

Results

288 unique HIV pol sequences were obtained from individuals in Tijuana between 2004-2016, including 46.4% from men-who-have-sex-with-men, 42.1% from individuals who reported transactional sex, and 27.8% from persons-who-inject-drugs (some individuals had >1 risk factor). 42.4% of sequences linked to at least one other sequence, forming 37 transmission clusters. Thirty-two individuals seroconverted during the observation period, including eight between April-July, 2016. Three of these individuals were putatively linked together. Qualitative interviews suggested that changes in policing led individuals to shift locations of residence and injection drug use, leading to increased risk taking (e.g., sharing needles).

Conclusions

Near-real time molecular epidemiologic analyses identified a cluster of linked transmissions temporally associated with policy shifts. Interviews suggested these shifts may have led to increased risk taking among individuals at high-risk for HIV acquisition. With all public policy shifts, downstream impacts need to be carefully considered, as even well-intentioned policies can have major public health consequences.