The study aims to develop and evaluate the efficacy and causal mechanisms of an interactive SMS intervention to optimize individual health and secondary HIV prevention benefits of ART in HIV-positive FSWs.

Antiretroviral therapy (ART) is highly effective at reducing the infectiousness of HIV-positive people, and is considered the cornerstone of all new HIV prevention approaches. A critical question is how to harness the potency of ART to reduce transmission from female sex workers (FSWs), a key population that has been central to HIV transmission in Africa for more than 25 years. In high prevalence countries like Kenya, FSWs represent about 1% of the population, yet contribute to one in seven (14%) new HIV infections. Targeting treatment as prevention (TasP) to FSWs could efficiently reduce HIV transmission on a population level. Effective TasP will require higher levels of ART adherence than those achieved in typical treatment programs. The rapid spread of mobile technology in Africa provides unique opportunities for mobile health (mHealth) interventions, which have been shown to be acceptable to providers and patients, and can improve ART adherence and suppression of plasma HIV viral load.

The ability of mobile (SMS) interventions to support ART adherence in key populations like FSWs and unique clinical scenarios such as TasP has yet to be evaluated. The investigators will answer these fundamental questions by addressing the following aims: 1) To use a qualitative rapid assessment and development approach to craft a theory-based, individualized, interactive SMS intervention, grounded in the Theory of Information, Motivation, and Behavior (IMB), to support ART adherence in HIV-positive FSWs, 2) To compare individualized, interactive SMS to standard care in achieving undetectable HIV VL 6 months post ART initiation in a randomized controlled trial (RCT) with 210 FSWs and 3) To administer an adaptation of the LifeWindows Information - Motivation - Behavioral Skills ART Adherence Questionnaire (LW-IMB-AAQ) to understand the mechanism of our SMS intervention's effect by comparing perceptions of support and motivation to adhere to ART in FSWs who received the intervention versus standard care.

Our overarching goal is to develop and evaluate the efficacy and causal mechanisms of an interactive SMS intervention to optimize individual health and secondary HIV prevention benefits of ART in HIV-positive FSWs. The aims of this project proceed sequentially from developmental (Aim 1) through implementation of the intervention (Aim 2) to evaluation of the fit with the behavioral model (Aim 3).

Inclusion Criteria:

• More than 18 years or emancipated minor
• Has access to mobile phone
• Self-identifying female sex worker
• Willing to receive study SMS messages
• HIV-positive (any WHO stage or CD4)
• Able to read or have someone else read
• ART naïve
• Informed consent obtained and signed.

Exclusion Criteria:

• Plans to move away in next 6 months
• Contraindication to ART