Effective strategies to promote HIV self-testing for men who have sex with men: Evidence from a mathematical model

A Review of Network Models for HIV Spread

BACKGROUND

HIV/AIDS has been a global health crisis for over 4 decades. Network models, which simulate human behavior and intervention impacts, have become an essential tool in guiding HIV prevention strategies and policies. However, no comprehensive survey of network models in HIV research has been conducted. This article fills that gap, offering a summary of past work and future directions to engage more researchers and inform policy related to eliminating HIV.

SETTING

Network models explicitly represent interactions between individuals, making them well-suited to study HIV transmission dynamics. Two primary modeling paradigms exist: a mechanistic approach from applied mathematics and a statistical approach from the social sciences. Each has distinct strengths and weaknesses, which should be understood for effective application to HIV research.

METHODS

We conducted a systematic review of network models used in HIV research, detailing the model types, populations, interventions, behaviors, datasets, and software used, while identifying potential future research directions.

RESULTS

Network models are particularly valuable for studying behaviors central to HIV transmission, such as partner selection and treatment adherence. Unlike traditional models, they focus on individual behaviors, aligning them with clinical practice. However, more accurate network data are needed for better model calibration and actionable insights.

CONCLUSIONS

This article serves as a point of reference for HIV researchers interested in applying network models and understanding their limitations. To our knowledge, this is the most comprehensive review of HIV network models to date.

A Perspective on Home-Based Sexual Health Care: Evidence, Access, and Future Directions

PURPOSE

This perspective explores the impact of home-based sexual health services on accessibility to STI and HIV testing for priority populations. This study evaluates home-based services as independent care options and as complementary components of traditional clinic-based care.

RECENT FINDINGS

Challenges for persons to attend clinic-based sexual health care can be overcome by offering lower threshold home-based sexual health care. Implementing home-based services has successfully reached priority populations, including previously untested men who have sex with men (MSM) and individuals with a high exposure risk for sexually transmitted infections (STI) including human immunodeficiency virus (HIV), attending location-based sexual health care. A challenge in home-based services is to ensure equitable care, such as for individuals with limited access to digital resources or low health literacy. While home-based sexual health services enhance the accessibility of sexual healthcare, to ensure equitable care, research into the needs of still underserved populations and subsequent tailoring of the care offered, is needed. Continuous monitoring and evaluation of the implementation of home-based services may maximize the advantages of this promising type of care.

The effects of HIV self-testing on HIV incidence and awareness of status among men who have sex with men in the United States: Insights from a novel compartmental model

BACKGROUND

The OraQuick In-Home HIV self-test represents a fast, inexpensive, and convenient method for users to assess their HIV status. If integrated thoughtfully into existing testing practices, accompanied by efficient pathways to formal diagnosis, self-testing could enhance both HIV awareness and reduce HIV incidence. However, currently available self-tests are less sensitive, particularly for recent infection, when compared to gold-standard laboratory tests. It is important to understand the impact if some portion of standard testing is replaced by self-tests. We used a compartmental model to evaluate the effects of self-testing in diverse scenarios among gay, bisexual and other men who have sex with men (MSM) in the United States for the period 2020-2030, and to understand which scenarios maximize the advantages of self-testing.

METHODS

We introduced a novel 4-compartment model for HIV self-testing. We employed the model under different screening rates, self-test proportions, and delays to diagnosis for those identified through self-tests to determine the potential effects of self-testing on HIV incidence and awareness of status when applied to the US MSM population. We studied scenarios in which self-tests supplement laboratory-based tests, with no replacement, and scenarios in which some replacement occurs. We also examined how future improvements in self-test sensitivity may affect our results.

RESULTS

When HIV self-tests are supplemental rather than substitutes for laboratory-based testing, self-testing can decrease HIV incidence among MSM in the US by up to 10 % and increase awareness of status among MSM from 85 % to 91 % over a 10-year period, provided linkage to care and formal diagnosis occur promptly following a positive self-test (90 days or less). As self-tests replace a higher percentage laboratory-based testing algorithms, increases in overall testing rates were necessary to ensure reductions in HIV incidence. However, such needed increases were relatively small (under 10 % for prompt engagement in care and moderate levels of replacement). Improvements in self-test sensitivity and/or decreases in the detection period may further reduce any necessary increases in overall testing by up to 40 %.

CONCLUSIONS

If properly utilized, self-testing can provide significant long-term reductions to HIV incidence and improve awareness of HIV status. Ensuring that self-testing increases overall testing and that formal diagnosis and engagement in care occur promptly following a positive self-test are necessary to maximize the benefits of self-testing. Future improvements in self-test sensitivity and reductions in the detection period would further reduce HIV incidence and the potential risks associated with replacing laboratory tests with self-tests.

Estimating the Cost-Effectiveness of HIV Self-Testing in the United States Using Net Benefit Regression

BACKGROUND

Cost-effectiveness analysis of HIV self-testing using patient-level data from a randomized clinical trial can inform HIV prevention funding decisions. Cost-effectiveness analysis using net-benefit regression addresses the sampling uncertainty in the trial data and the variability of policymakers' willingness to pay (WTP).

METHODS

We used published data from a 12-month longitudinal randomized clinical trial that enrolled 2665 men who had sex with men randomly assigned to the self-testing arm (participants receiving self-test kits) and control arm (participants receiving standard-of-care), and the self-testing arm identified 48 additional new HIV cases. We used net-benefit regression to investigate the cost-effectiveness of an HIV self-testing intervention, which compared the incremental cost per new HIV diagnosis with policymakers' WTP thresholds. We addressed the uncertainties in estimating the incremental cost and the policymakers' WTP per new diagnosis through the incremental net-benefit (INB) regression and cost-effectiveness acceptability curve (CEAC) analyses.

RESULTS

From the health care provider's perspective, the INB analysis showed a positive net benefit of HIV self-testing compared with standard-of-care when policymakers' WTP per new HIV diagnosis was $9365 (95% confidence interval: $5700 to $25,500) or higher. The CEAC showed that the probability of HIV self-testing being cost-effective compared with standard-of-care was 58% and >99% at a WTP of $10 000 and $50 000 per new HIV diagnosis, respectively.

CONCLUSION

The INB and CEAC analyses suggest that HIV self-testing has the potential to be cost-effective for relatively low values of policymakers' WTP.

Could Home Human Immunodeficiency Virus Self-Testing Ever Become a Game Changer?

Could home human immunodeficiency virus (HIV) self-testing make a major difference in identifying persons with undiagnosed HIV in the United States? We argue that approval of new self-test assays for home use would help but must be combined with extensive investment in community outreach and linkage to care to make an impact.

Intention to use and acceptability of home-based sexual health care among men who have sex with men who previously attended clinic-based sexual health care

The COVID-19 pandemic has temporarily disrupted access to clinic-based sexual health care for men who have sex with men (MSM) in the Netherlands. The importance of home-based sexual health care has been underpinned as an extension of clinic-based care. This paper aims to assess intention to use, and acceptability of home-based sexual health care among MSM who previously attended clinic-based sexual health care. In November 2020, 424 MSM who had attended an STI clinic pre-pandemic were invited to participate in an online survey; 154 MSM completed the survey (response 36%). Intention to use self-sampling STI/HIV tests was assessed (median; scale 0–100) and compared across sociodemographic and sexual behavior characteristics by Kruskal-Wallis H tests. Descriptive analyses provided insights in acceptability of home-based sexual health care. Of participants (median age 47), 60.4% (93/154) tested for STI/HIV in the past 6 months, most of them attended a clinic. The median score on intention to use self-sampling tests was 86.5 (SD = 33.4) and did not differ by sociodemographic or sexual behavioral characteristics (all p-values > 0.1). Participants were positive toward online sexual health counseling (median attitude = 75.0, SD = 29.6) and their main preferred topics were PrEP use and STI/HIV testing. MSM who attended clinic-based care expressed intention to use self-sampling tests and a positive attitude toward online sexual health counseling. Home-based sexual health care elements are not currently integrated within Dutch clinic-based sexual health care and should be considered an addition for continued provision of care and extended reach of MSM.

Modeling the Impact of HIV-1 Nucleic Acid Testing Among Symptomatic Adult Outpatients in Kenya

BACKGROUND

Up to 69% of adults who acquire HIV in Kenya seek care before seroconversion, providing an important opportunity for early diagnosis and treatment. The Tambua Mapema Plus (TMP) trial tested a combined HIV-1 nucleic acid testing, linkage, treatment, and partner notification intervention for adults aged 18-39 years with symptoms of acute HIV infection presenting to health facilities in coastal Kenya. We estimated the potential impact of TMP on the Kenyan HIV epidemic.

METHODS

We developed an agent-based network model of HIV-1 transmission using TMP data and Kenyan statistics to estimate potential population-level impact of targeted facility-based testing over 10 years. Three scenarios were modeled: standard care [current use of provider-initiated testing and counseling (PITC)], standard HIV rapid testing scaled to higher coverage obtained in TMP (scaled-up PITC), and the TMP intervention.

RESULTS

Standard care resulted in 90.7% of persons living with HIV (PLWH) knowing their status, with 67.5% of those diagnosed on treatment. Scaled-up PITC resulted in 94.4% of PLWH knowing their status and 70.4% of those diagnosed on treatment. The TMP intervention achieved 97.5% of PLWH knowing their status and 80.6% of those diagnosed on treatment. The percentage of infections averted was 1.0% (95% simulation intervals: -19.2% to 19.9%) for scaled-up PITC and 9.4% (95% simulation intervals: -8.1% to 24.5%) for TMP.

CONCLUSION

Our study suggests that leveraging new technologies to identify acute HIV infection among symptomatic outpatients is superior to scaled-up PITC in this population, resulting in >95% knowledge of HIV status, and would reduce new HIV infections in Kenya.

Awareness and Use of HIV Self-Testing Among Men Who Have Sex With Men Remains Low in Spain 2 Years After Its Authorization

Objectives

HIV self-testing has been available in Spain since 2017 as a diagnostic tool to promote earlier diagnosis. We aimed to assess awareness and previous use of HIV self-testing in a sample of men who have sex with men (MSM) recruited online more than 2 years after its legal authorization in Spain.

Methods

We analyzed 5,492 MSM recruited between May and July 2020 in gay dating apps/websites and other social networks. We estimated the proportion of participants who were aware of the existence of HIV self-testing and the proportion who reported previous use. To identify factors associated with both outcomes we built two Poisson regression models. Among those who reported previous use we described several aspects related to their last self-test.

Results

Awareness of HIV self-test was reported by 29.7% and its previous use by 5% of participants. Awareness was independently associated with recruitment in gay dating apps/websites, being ≥40 years old, born in Spain-other European countries, having higher educational level, living in medium-small municipalities and living sex life openly. Independent associations were also found with having received a sexually transmitted infection diagnosis (STI) or an HIV negative test in the last 12 months, and being HIV positive. Use was significantly higher among participants who were paid for sex or diagnosed with an STI in the last 12 months and who received their last HIV test in the preceding year. Self-testing occurred recently, with kits acquired at pharmacies and carried out alone.

Conclusion

Awareness and use probably have not increased sufficiently in order to make a relevant impact to the promotion of early HIV diagnosis. Additional efforts, mainly focused on less favored MSM, should be made to take better advantage of the possibilities offered by this testing option.