HIV prevention strategies and risk of infection: a model-based analysis

Abstract

Risk populations for HIV infections tend to neglect condom use, making alternative preventive approaches necessary. Accordingly, we modelled the risk of sexual HIV transmission for condom use vs. use of rapid diagnostic test (RDT) systems with subsequent exclusion of potential sexual partners with a correctly or falsely positive test from unprotected sex with and without the use of HIV pre-exposure prophylaxis (PrEP) in a bio-statistical approach. We combined a previously described model of transmission risk for HIV-exposed individuals with a newly suggested model of risk of HIV exposure for sexually active HIV-negative individuals. The model was adapted for several stages of infection and different strategies of HIV infection prevention.HIV prevention with RDTs can reduce the transmission risk by up to 97% compared with having sex without any prevention and up to 80% compared with condom use. Nevertheless, RDT-based prevention strategies demonstrate a lack of protection in several stages of infection; in particular, RNA-based RDT systems may fail under treatment. RDT-based pre-screening of potential sex partners prior to unprotected sexual contacts substantially reduces HIV transmission risk. Combination of different prevention strategies is advisable for high-risk groups.

Diagnostics as prevention — a rapid testing-based strategy of sex workers against sexual HIV exposure

“…Unprotected sexual contact with HIV-infected individuals in the seroconversion stage is particularly dangerous because the transmission risk is increased by factor 10 to 100 compared to the baseline risk during the chronic stage of infection due to very high viral loads [ 18 ]. As this study models exposition risks and not transmission risks, respective estimations would be beyond its scope but are described in detail elsewhere [ 1 ]. As also detailed there [ 1 ], molecular RDT systems based on nucleic acid amplification (NAT) might be applied to solve the problem of lacking sensitivity in the early infection stages.…”

“…As this study models exposition risks and not transmission risks, respective estimations would be beyond its scope but are described in detail elsewhere [ 1 ]. As also detailed there [ 1 ], molecular RDT systems based on nucleic acid amplification (NAT) might be applied to solve the problem of lacking sensitivity in the early infection stages. Due to financial and logistic reasons, however, the application of NAT-based RDT systems for leisure purposes will be restricted to well-equipped and resource-rich hedonistic communities and appears less likely to be deployed.…”

“…Based on these assumptions and our recently published modeling approach [ 1 ], the model presented here was established as described in Results section.…”

“…Recently, we have introduced a mathematical model for the comparison of prevention strategies against sexual transmission of the human immunodeficiency virus (HIV) [ 1 ] with a focus also on exposition prevention. Although condom use is the recommended procedure to prevent an HIV infection during risky sexual contacts, a Cochrane review [ 2 ] has estimated the effectiveness of condoms in reducing HIV transmission by 80% in heterosexual settings.…”

“…In spite of these limitations, an estimated protection rate of 80% can be considered as widely accepted and was therefore used for further calculations. However, the main limitation is not technical failure of condom use, but rather its lacking acceptance in high-risk groups as extensively discussed elsewhere [ 1 , 9 ].…”