Effectiveness of Using Additional HIV Self-Test Kits as an Incentive to Increase HIV Testing within Assisted Partner Services

Incentives have shown mixed results in increasing HIV testing rates in low-resource settings. We investigated the effectiveness of offering additional self-tests (HIVSTs) as an incentive to increase testing among partners receiving assisted partner services. Western Kenya We conducted a single-crossover study nested within a cluster-randomized controlled trial. Twenty-four facilities were randomized 1:1 to 1) control: provider-delivered testing, or 2) intervention: offered one HIVST or provider-delivered testing for six months (pre-implementation), then switched to offering two HIVSTs for six months (post-implementation). A difference-in-differences approach using generalized linear mixed models, accounting for facility clustering and adjusting for age, sex, and income, was used to estimate the effect of the incentive on HIV testing and first-time testing among partners in APS. March 2021-June 2022, 1127 index clients received APS and named 8155 partners, among whom 2333 reported a prior HIV diagnosis and were excluded from analyses, resulting in 5822 remaining partners: 3646 (62.6%) and 2176 (37.4%) in the pre- and post-implementation periods respectively. Overall, 944/2176 (43%) partners were offered a second HIVST during post-implementation, of whom 34.3% picked up two kits, of whom 71.7% reported that the second kit encouraged HIV testing. Comparing partners offered one vs. two HIVSTs showed no difference in HIV testing (relative risk[RR]:1.01, 95%Confidence Interval[CI]:0.951-1.07) or HIV testing for the first time (RR:1.23, 95%CI:0.671-2.24). Offering a second HIVST as an incentive within APS did not significantly impact HIV testing or first-time testing, although those opting for two kits reported it incentivized them to test.