Comparison of HIV self-test distribution modalities to reduce HIV transmission and burden in western Kenya: a mathematical modelling study

Abstract

Objectives: To compare the impact of different HIV self-testing (HIVST) distribution modalities on population-level HIV outcomes.

Design: Mathematical modelling study.

Setting: Six counties in western Kenya.

Methods: We projected population-level HIV outcomes among individuals aged 15+over 30 years (2022-2052) using EMOD-HIV, an agent-based network transmission model calibrated to the HIV epidemic in western Kenya. We simulated the impact of three HIVST distribution modalities: (1) secondary distribution to male partners via women who attend antenatal care visits ('ANC'); (2) secondary distribution to partners of individuals newly diagnosed with HIV at health facilities ('partner services'); and (3) distribution to any individuals attending outpatient clinics ('outpatient'). We informed our model assumptions on HIV testing uptake for each HIVST distribution modality using the estimates from a meta-analysis of randomised clinical trials published between 2006 and 2019 and compared the outcomes for each HIVST distribution modality to standard testing without HIVST.

Outcomes measures: The number of HIV tests performed (HIVST and non-HIVST), HIV diagnoses, HIV infections, and HIV-related deaths.

Results: With standard testing alone, the average number of HIV tests was 4.69 million per year, amounting to 81.0 tests per 100 adults. The average number of tests per year increased by 2.9% with ANC, 0.6% with partner services, and 23.7% with outpatient distribution of HIVST. Compared with standard testing alone, partner services with HIVST will avert the largest number of new HIV infections (10.2%, 95% CI 9.9% to 10.5%), followed by outpatient distribution (8.5%, 95% CI 8.2% to 8.7%) and ANC (6.1%, 95% CI 5.8% to 6.3%). Compared with standard testing, the number of HIVST needed per one additional HIV infection averted was 216 with ANC, 17 with partner services and 2009 with outpatient, while the number of HIVST per one additional HIV-related death averted was 364 with ANC, 17 with partner services and 3851 with outpatient.

Conclusions: Secondary distribution of HIVST to partners of individuals newly diagnosed with HIV could prevent the most HIV infections and HIV-related deaths. HIVST can be an important strategy to improve uptake of testing and long-term population-level health effects.

Keywords: Africa South of the Sahara; Epidemiology; HIV & AIDS.

Figure 1. Number of HIV tests per year by HIVST distribution modalities. ANC, secondary distribution through women who attended antenatal care visits to their male partners; Partner services, secondary distribution through individuals newly diagnosed with HIV to their current sexual partners; Outpatient, distribution of HIVST at outpatient facilities. ANC, antenatal care; HIVST, HIV self-testing; SoC, standard of care.

Figure 2. (A) HIV infections averted and (B) HIV-related deaths averted between 2022 and 2051 by different HIVST distribution modalities, compared with the standard of care testing only. For each distribution modality, ‘mean’ represents the results assuming the mean effect of HIVST testing uptake from the meta-analysis, while ‘low’ and ‘high’ represent the results assuming the lower and upper bounds of the 95% CI for the effects of HIVST testing uptake in the meta-analysis, respectively, while holding all other parameter values constant. The error bars represent the 95% CI from bootstrap analysis of 250 simulations. ANC, secondary distribution through women who attended antenatal care visits to their male partners; Partner services, secondary distribution through individuals newly diagnosed with HIV to their current sexual partners; Outpatient, distribution of HIVST at outpatient facilities. ANC, antenatal care; HIVST, HIV self-testing.

Figure 3. Estimated percentages of individuals diagnosed with HIV among those living with HIV by HIVST distribution modalities: (A) males and (B) females. The purple line indicates 95% (ie, the ‘First 95’ of the UNAIDS 95-95-95 targets). The dotted line indicates the year when the simulation starts (2022). ANC, secondary distribution through women who attended antenatal care visits to their male partners; Partner services, secondary distribution through individuals newly diagnosed with HIV to their current sexual partners; Outpatient, distribution of HIVST at outpatient facilities. ANC, antenatal care; HIVST, HIV self-testing; SoC, standard of care.