Network Targeting of HIV Preexposure Prophylaxis to Men Who Have Sex With Men Open Access

Prasad, Pragati (Spring 2019)

Permanent URL: https://etd.library.emory.edu/concern/etds/000001006?locale=en
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Abstract

Background    

Partnership concurrency plays a critical role in HIV/STI transmission dynamics. Network connectivity is expanded due to concurrency, allowing for rapid HIV transmission within sexual networks of men who have sex with men (MSM). Because of this, network-based behavioral indications may be efficient strategies for targeting HIV preexposure prophylaxis (PrEP).

Methods          

We used stochastic network-based models of HIV transmission dynamics among MSM to estimate the impact of PrEP delivered based on network features. Connectivity within the network was determined by index and partner degree. We estimated the percentage of infections averted (PIA) and the number of person-years on PrEP to prevent one HIV infection (NNT) under the CDC’s clinical practice guidelines (standard of care) compared to network-based indications. We modeled the contribution of network indications while varying the partner thresholds for them, also considering varied coverage, risk window, and risk reevaluation parameters.

Results            

Compared to a counterfactual model in which there was no PrEP coverage, the CDC guidelines scenario averted 15.1% of HIV infections, while the network-based scenario (index and partner degree) averted 11.4%. However, the network-based scenario only required 18 person-years on PrEP to prevent 1 new HIV infection, while the CDC scenario had an NNT of 24. The index degree indication on its own performed better than the partner degree indication in every variation of parameters. Increasing the probability of starting PrEP from 35% (base parameter) to 60% was associated with an increase in the percent of averted infections in both the CDC scenario (23.4%) and the network scenario (18.7%).

Conclusions    

Using network-based indications to target MSM for PrEP in place of the current CDC indications averts fewer overall infections but require less person-time on PrEP. As PrEP coverage continues to increase, network indications provide insight into an efficient way to distribute men along the MSM population.

Table of Contents

Introduction.……………………………………………..…………………………………………………………....6

Methods.……………………………………………..………………………………………………………………....7

Study Design..………………………….………………………………………………………………….............7

HIV Transmission & Progression..………………………….…………………………………………….......7

PrEP Targeting..………………………….……………………………………………...……………….............8

Simulation..………………………….……………………………………………...…………………….............9

Results.……………………………………………..…………………………………………………………............10

Discussion.……………………………………………..………………………………………………………….......12

Limitations.................................................................................................................................13

Conclusions................................................................................................................................14

Tables.............................................................................................................................................15

Figures............................................................................................................................................22

References......................................................................................................................................24

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