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

Abstract

IntroductionGerman sex workers have illegally established a prevention strategy, which consists of testing potential sexual partners with human immunodeficiency virus (HIV)-specific rapid diagnostic tests (RDTs) prior to engaging in unprotected sexual intercourse eventually performed in case of a negative test result. Based on a recently established modeling approach, the effectiveness of this strategy regarding the risk of HIV exposure was compared with protection provided by condom use.MethodsBased on a literature search, the following assumptions were used for the calculations: an averaged 80% exposure risk reduction with a condom used during sexual intercourse, usage of a well-characterized 4th-generation HIV RDT, and a 10 day post-infection period without any measurable viral load in peripheral blood followed by a sero-conversion period of about 3 weeks with 12.3% test sensitivity (antigen-specific) and only afterwards 97.3% (antibody-specific) test sensitivity.ResultsIn most constellations, the HIV exposure risk in case of RDT-based prevention was lower than with condom use. Conclusions: The RDT-based HIV exposure prevention as established by sex workers is effective in most situations. A notable weakness of the strategy is the RDTs' poor sensitivity in spite of a high transmission risk during the seroconversion stage.

Diversification of the Prevention of Sexually Transmitted Infections

“…Another concept for the prevention of sexual transmission of HIV, widely neglected by preventative medical science, was semi-legally implemented by sex workers [16]. Sex workers, who offered unprotected sexual intercourse to maximize profitability, protected themselves from HIV transmission by performing HIV rapid tests on their clients and engaging in unprotected intercourse only in the event of a negative test result.…”

“…Since legal concerns make it hard to empirically investigate the diagnostics-as-prevention concept as applied by sex workers, evaluation by mathematical modeling has been performed. This is possible, because first, there are very good prevalence and incidence data on HIV infection available, and second, the infectiousness of the virus is very well characterized as a function of the situational context, and third, from evaluation studies, very exact results on the performance of diagnostic HIV tests exist [16,17].…”

“…Interestingly, it became obvious from modeling that the diagnostics-as-prevention concept as implemented by sex workers allows an even greater reduction of the exposure risk to HIV than the mere use of condoms in most situations [16]. The weakness of the immunochromatographic rapid tests in the early infection phase can be partially compensated if additional PCR-based rapid tests are used, which are increasingly available as point-of-care-testing options [17].…”

Sexually transmitted infections in soldiers – a cross-sectional assessment in German paratroopers and navy soldiers and a literature review

“…The US Navy and Marine Corps established a Sexual Health and Responsibility Program (SHARP) to coordinate activity in the field of STI prevention programs [46]. In line with the known preventive effects of early diagnosis and treatment [47][48][49], military entry screenings for STIs have been recommended as a strategy of reducing STIs within the military community [50]. Data evaluating the preventive effects of prevention programs addressing STIs in the military setting are, however, still missing.…”

Optimization of Case Definitions for Sensitivity as a Preventive Strategy—A Modelling Exemplified with Rapid Diagnostic Test-Based Prevention of Sexual HIV Transmission

“…It should be noted here that the probability of the occurrence of the symptoms may differ and that they are therefore Poisson binomially distributed. As recently demonstrated by our group based on three previous modelling approaches [8][9][10] and summarized in a mini-review [11], a combination of self-testing and the testing of potential sexual partners applying traditional or molecular rapid diagnostic testing (RDT) strategies can be a promising approach for the transmission prevention of sexually transmitted infections (STIs) for individuals who do not want to use condoms. As discussed previously [8][9][10][11][12], the effectiveness of such test-based preventive strategies depends on various factors, including the availability of reliable and easy-to-apply diagnostic point-of-care-testing (POCT) solutions even for diagnostic laymen, window-periods of the applied tests as well as the tests' sensitivity and specificity.…”