Redefining Success With Oral PrEP: A call for better metrics
In June 2019, Jhpiego and the Prevention Market Manager (implemented by AVAC & CHAI) convened a think tank of PrEP experts to examine current methods for monitoring and evaluating (M&E) PrEP use. The meeting explored the limitations of these methods, and issued preliminary recommendations for a new generation of metrics that better capture the use and impact of daily oral PrEP. (Figure 1 & 2)
Many stakeholders have borrowed definitions and indicators to evaluate the effectiveness of antiretroviral therapy (ART) programs. But PrEP is not synonymous with ART. Risk is not constant for eligible PrEP users, it can be seasonal or event-driven (ED).
The WHO updated its definition of effective use of PrEP for prevention in July 2019, recommending ED for men who have sex with men (MSM) who face infrequent exposure to HIV risk, and continuing to recommend daily dosing for all populations facing an ongoing high-risk of exposure. The evidence among MSM shows discontinued and restarted PrEP may be highly effective for this population.
The field urgently needs M&E metrics to reflect the variations in risk and use to inform innovation in program delivery, to maximize PrEP’s impact at the population level, and to better protect individual PrEP-users from HIV.
Think tank participants included representatives from normative bodies, funders, PEPFAR agencies, implementers, other partners in PrEP advocacy and delivery, and statisticians.
1. PrEP continuation should be considered fluid. Successful use will depend on the individual’s needs and state of risk at given points in time. PrEP continuation and ART retention are not analogous; PREP_CURR and TX_CURR (PEPFAR codes indicating an end-user is current on PrEP or treatment) require different interpretations.
Figure 1—Considerations for Implementation and Impact, developed by the CHAI under the Prevention Market Manager led by AVAC
2. While HIV risk can be continuous or episodic, only continuous PrEP use provides protection for all. For this reason, preferring continuous use—and monitoring for it—may be the goal of routine M&E. PrEP continuation can be primarily measured by tracking the date and volume of PrEP dispensed. For most programs, this can be done by collecting a snapshot of the data over a specific period, a cross-sectional measure, which is feasible to implement based on available tools and M&E systems.
Following a cohort of clients over a long period time, client-level longitudinal monitoring, among a subset of programs or sites can help to validate cross-sectional measurements. This approach will allow for more accurate and closer tracking of patterns of PrEP use and account for changes in risk. However, client-level longitudinal monitoring requires electronic medical records and databases.
3. Successful PrEP implementation and impact may be assessed by reaching a certain threshold of PrEP use in a given community, a measure of saturation, as long as sufficient information is available regarding PrEP coverage and HIV incidence in sub-populations.
Figure 2—Tracking Impact: Searching for a solution, sexual reproductive health (SRH) programs use CYP as a proxy for impact.
Think tank recommendations can be applied across geographies, contexts, oral PrEP regimens (including event-driven), and future HIV preventative technologies in the pipeline. At this time, the think tank proposes these definitions and methods for oral PrEP programs and urge normative bodies to support them to ensure continuity and comparability.
Modifications to current PrEP M&E approaches:
- Report PrEP_NEW (PEPFAR code to document new uptake by an individual) every 3 months. Disaggregated by key population, age, and pregnancy/breastfeeding status.
- Add an indicator to measure the distribution of PrEP (i.e. number of pills or bottles distributed, combined with the number of individuals prescribed PrEP/population size) as a proxy for impact. This will establish a baseline to look at the impact of PrEP in the context of saturation coverage, similar to the approach used in the U.S and other high-income settings. This could potentially be relevant and applicable to future PrEP technologies.
- Pilot test, or discuss with national technical working groups (TWGs) the potential for piloting an impact indicator (see above) based on the distribution in settings where PrEP is sufficiently scaled-up.
- Support both cross-sectional and longitudinal approaches for collecting data on effective use at the program level. Compare and contrast the two approaches at the global level for feasibility, data quality and impact planning to target programmatic interventions.
- Support program evaluations and implementation science to identify the reasons for oral PrEP discontinuation and, if related to program quality, identify effective interventions and strategies to improve the quality of PrEP programs and a better understanding of episodic or sporadic use.