Introduction We assessed willingness to use pre-exposure prophylaxis (PrEP) to prevent HIV among female sex workers (FSWs) in Tijuana and Ciudad Juarez, two northern Mexico cities bordering the United States (US).

Methods To date (7/2016-12/2016), 279 HIV-negative FSWs in a behavioural HIV prevention intervention trial have tested for sexually transmitted infections (STIs) and completed surveys to assess (1) preferences between and willingness to use 12 hypothetical PrEP products with varying attributes with respect to formulation (pill, gel, douche, or ring), frequency of use, cost, effectiveness, side effects, and access point and (2) perceived motivators and barriers to PrEP use. Fisher’s exact tests were used to examine differences in willingness to use preferred PrEP products by STI diagnosis and sociodemographic, behavioural, and sex work characteristics.

Results 94% (263/279) of FSWs were willing to use their preferred PrEP product. Willingness to use preferred PrEP products was lower among FSWs diagnosed with an STI (83% vs. 97%; p=0.001), living in Tijuana (88% vs. 99%p<0.0001), primarily practicing sex work on the street (89% vs. 97%; p=0.01), reporting methamphetamine use (past month) (86% vs. 97%; p=0.001), and reporting hazardous alcohol consumption (past year) (91% vs. 97%; p=0.04). Of the 16 FSWs unwilling to use PrEP, “PrEP does not provide full protection against HIV” was the most common perceived barrier to PrEP use (88%) followed by “I would have trouble using PrEP consistently because of my alcohol use” (63%) and “I am worried I will lose clients if I use PrEP because they will assume I am HIV-positive” (63%). All FSWs unwilling to use PrEP reported that additional protection against other STIs would motivate them to use PrEP.

Conclusion PrEP interest was high among FSWs along the Mexico-US border. Our findings suggest that the development of multi-purpose PrEP products and site-specific interventions that provide PrEP education and address substance use and clients’ perceptions as barriers to PrEP use may support FSWs’ future PrEP uptake.