This study will implement an intervention in a two-year randomized controlled trial (RCT) to establish efficacy on viral suppression as a biological endpoint, compare the effectiveness of two different modes of implementation (including one entirely based on readily available clinic data), and investigate cost-effectiveness. Participants in the first intervention group (T1, n=110) will be eligible for small lottery prizes based on timely clinic visits, and qualify for an annual lottery conditional if demonstrating viral suppression; those in the second group (T2, n=110) will draw prizes conditional on electronically measured adherence at each clinic visit, and also participate in an annual lottery that is conditional on high adherence throughout the year. The control group (n=110) will receive the usual standard of care. Assessments will be conducted at baseline and then every six months. Primary outcomes are undetectable viral load and electronically measured adherence.

It is imperative to find ways to boost ART adherence in sub-Saharan Africa where adherence rates have been found to decline over time, and where treatment options such as second-line regimens are limited. A promising tool is the use of incentives based on insights from behavioral economics (BE) for healthy HIV-related behavior. The proposed R01 study is based on the results of the PI's R34 'Rewarding Adherence Program (RAP)' [R34 MH096609] that demonstrated feasibility and acceptability of incentives allocated by a drawing for HIV-related behaviors, and established preliminary efficacy. The current R01 study builds on these promising results with the aim to a) use viral loads as biological endpoints that were not included in the R34 for cost reasons; b) establish efficacy in a fully powered intervention as well as comparative efficacy of two different ways of implementing the incentives including one arm that has been adapted to changing clinical guidelines and can be implemented with readily available data from clinic records; and c) assess the cost effectiveness of these two implementation modes as a further input for policy-makers. The intervention is targeted at increasing the motivation of HIV clients who have been on ART for several years through the benefit and joy of prize drawings, thereby attempting to overcome the treatment 'fatigue' that can develop in the context of mundane, daily pill taking over the course of life-long treatment. Insights from behavioral economics suggest that such an intervention may be particularly effective for people with present bias (those who have a tendency to give in to short-term temptation at the cost of more long-term benefits) that was found to be prevalent among HIV clients in the R34 study. The intervention will be implemented among 330 adult clients in three groups: for the first intervention group, timely clinic attendance will constitute the eligibility criteria for participating in a prize drawing at each scheduled clinic visit; participants are also eligible for an annual prize drawing based on showing viral suppression. The second treatment group will be incentivized on demonstrated high ART adherence between clinic visits that also determine the winning chances at an annual prize drawing. The control group will receive the usual standard of care. All participants will receive MEMS caps to record adherence and assessments over 24 months (at baseline and every 6 months thereafter). The first Specific Aim will be to evaluate the effectiveness of the intervention; the second aim is to compare the relative effectiveness of the adherence-based arm and the arm directly incentivizing viral suppression that uses only data readily available in the clinic. The third Specific Aim is to perform a comparative cost-effectiveness analysis of the two intervention arms as a further policy input. If proven efficacious, the intervention as implemented in the newly adapted arm based on viral load suppression can be readily taken over by the clinic and scaled at low cost to other clinics.

In the study also 70 treatment initiating clients (in addition to the 330 treatment mature clients described above) will be recruited, but they will be excluded from the main analysis. [Note on 9/7/2019: due to funding, we will not recruit this additional sample of treatment initiating clients]

Inclusion Criteria:

• 18 years of age or older
• at Mildmay clinic on ART for at least two years
• adherence problems in the last six months

Note: for the 70 treatment initiators to be recruited in addition to the main sample of 330 treatment-mature clients (on which the main analysis will focus), the inclusion criteria are:

• 18 years of age or older
• started on ART at Mildmay clinic within the last six months

Exclusion Criteria:

• not able to understand the consent form and study procedures
• language other than Luganda or English
• not willing to consistently use the MEMS caps device for adherence measurement

The investigator and outcomes assessor will be blinded to treatment assignment of study participants.