# Community tenofovir levels as a population adherence measure to understand the impact of oral PrEP on HIV acquisition among young women in sub-Saharan Africa

> **NIH NIH R21** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $300,383

## Abstract

PROJECT SUMMARY
Pre-exposure prophylaxis (PrEP) works at an individual-level to prevent HIV acquisition and is currently being
rolled out globally to people at high risk for HIV acquisition— particularly among the high priority population of
young women in sub-Saharan Africa. With the UNAIDS goal of 3 million people receiving PrEP globally by
2020, population-level metrics are needed to understand if PrEP delivery programs are achieving effective HIV
prevention. For antiretroviral therapy (ART), community viral load provides insight into infectiousness. Similarly,
measures of community PrEP use and HIV risk may provide insight for PrEP delivery and identify gaps in client
outreach and adherence support. In this R21 application, we will develop the first ever model of “community
tenofovir levels”. We will build on our existing HIV transmission model (which includes HIV incidence, ART
uptake, viral suppression, and assumptions of PrEP adherence and HIV risk) and leverage objective PrEP
adherence data and multiple assessments of HIV risk from an ongoing cohort study of 350 young women
taking PrEP in Kenya, called MPYA (Monitoring PrEP in Young Adult women). We propose the following aims:
1. Measure tenofovir diphosphate (TFV-DP) levels in archived and unanalyzed dried blood spots (DBS) from
the MPYA cohort. Funding is currently available for a 15% random sample of participant visits. We propose to
analyze additional 500 DBS that will enable a more complete characterization of the first year of PrEP use.
2. Adapt an existing HIV transmission model to use heterogeneity in community tenofovir levels and HIV risk to
estimate the impact of PrEP on HIV acquisition in young women in sub-Saharan Africa.
 2a. Building on our current HIV transmission model, we will add DBS TFV-DP levels (Aim 1) plus sexual
 behavior from the MPYA cohort to estimate an “effective community tenofovir level” (i.e., the proportion of
 condomless sex acts protected by tenofovir). This effort will involve parameterization of our HIV
 transmission model and validation with data from three other studies of PrEP in young African women.
 2b. Use the new PrEP impact model (Aim 2a) to estimate the community tenofovir levels needed among
 young women by age and risk group to decrease HIV incidence at an individual and population level.
Investigators for this proposal consist of leaders in the fields of PrEP adherence (Dr. Haberer) and HIV
modeling (Dr. Barnabas) with critical contextual input from a PrEP delivery expert (Dr. Irungu). This proposal
reflects a novel approach to population-level adherence estimation that could provide much needed guidance
for the rollout of PrEP in sub-Saharan Africa. It builds and extends on the solid scientific premise of research
showing the importance of adherence in PrEP effectiveness, as well as the potential for population-level
information from objective biomarkers. The products of the proposal thus have great potential to both advance
science and mo...

## Key facts

- **NIH application ID:** 10028436
- **Project number:** 1R21MH121156-01A1
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Ruanne Vanessa Barnabas
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $300,383
- **Award type:** 1
- **Project period:** 2020-09-17 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10028436

## Citation

> US National Institutes of Health, RePORTER application 10028436, Community tenofovir levels as a population adherence measure to understand the impact of oral PrEP on HIV acquisition among young women in sub-Saharan Africa (1R21MH121156-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10028436. Licensed CC0.

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