SMS, AI, and behavioral design come together to maximize medication adherence

We helped Prepmate achieve adherence rates in the 90's with a stigmatized drug and a challenging population

Young men who have sex with men (YMSM) and transgender women (TGW) are among the highest at- risk for HIV in the US. While PrEP has demonstrated efficacy in clinical trials, adherence has been low among YMSM and TGW. In partnership with San Francisco’s Department of Health and UCSF, we developed a youth-tailored, SMS-based PrEP support intervention (Prepmate) and evaluated PrEP initiation and early adherence.

The challenge of preventing HIV in this population was multi-layered. Taking a preventive medication for HIV has stigma (considered an indicator of promiscuity), the recency of PrEP’s development brings relatively low trust and high prevalence of misinformation, and the demographic targeted faces comparatively high rates of mental illness, homelessness (or transience), and relational difficulty. Moreover, the group frequently engaged in risky behaviors, such as unprotected sex and intravenous drug usage, which meant that an underperforming solution could potentially put participant’s lives at risk.

With a complex problem and a challenging population, a solution would not be simple.

Some of our contributions included:

Designing a brand that would resonate with the audience

Literature review on medication adherence and SMS interventions

Product design for a starter toolkit, including custom pillboxes

Design of medication adherence strategy and messaging automation

Determination of rules and chatbot logic for handling inbound messaging

Development of HIPAA-compliant web product to deliver and manage SMS communication and triage responses



Participants with detectable medication levels at end of the first 4 weeks, a critical window for habit development


Participants with sufficient medication in blood samples within the highest level of HIV protection at 4 week follow-up


Higher rates of adherence compared to a similar study at the same follow-up point (ATN 13)

Adherence levels on the Prepmate solution compare extremely favorably to similar interventions with similar populations. While the trial is still ongoing, if adherence reduction rates decline in proportion to previous studies over time, Prepmate may prove to be among the most effective methods ever tested for medication adherence with PrEP.

Could behavioral science help your team make a greater impact?