BACKGROUND: As countries achieve 90-90-90 targets, identifying the remaining undiagnosed people living with HIV (PLHIV) requires innovative and affordable approaches. Here we assess costs of secondary HIV self-test (HIVST) kit distribution through antenatal clinic (ANC) attendees, including 'Index' (newly diagnosed) HIV patients, as part of randomized controlled trial in Malawi.
METHODS: Full and incremental (only direct) costs of a three-arm pragmatic trial randomizing 27 government primary clinics were estimated using ingredients-based costing. Standard of care (SoC) invited partners to attend HIV testing services. In HIVST arms, ANC/Index clients received HIVST kits. HIVST+incentive offered partners US$10 to confirm their HIVST result at the clinic regardless of the HIVST result. HIVST interventions were integrated and delivered by un-incentivized government staff. Unit cost per kit/invitation letter distributed and per partner-tested were estimated for each arm.
RESULTS: Uptake of partner-testing increased substantially across arms: from 38.6% SoC to 77.1% and 62.9% in the HIVST-only and HIVST+Incentive arms, respectively. Costs were higher in the HIVST arms (Table 1) but with reach to substantially more partners. To test one partner required distribution of 2.6 letters in SoC, and 1.3 and 1.6 kits, respectively, in HIVST-only and HIVST+Incentive arms. Incremental unit costs per letter/kit distributed were: US$1.79 SoC, US$5.16 HIVST-only and US$5.06 HIVST+Incentive arm. While incremental unit costs per reported partner testing were: US$5.62 SoC, US$6.57 HIVST-only and US$19.08 HIVST+Incentive (linkage) arm (Table).

Scenario Analysis: full and incremental costs of HIV Self-Test Integration

Cost Item	Numbers and Full Unit Costs (US$) per ANC/Index partner tested*			Numbers and Incremental Unit Costs (US$) per ANC/Index partner tested
	SoC	HIVST-Only	HIVST+ Incentives	SoC	HIVST-Only	HIVST+ Incentives
Number Kits/Letters distributed	1,550	1,609	1,829	1,550	1,609	1,829
Number (%) Partners HIV-testing	599 (38.6%)	1,241 (77.1%)	1,151 (62.9%)	599 (38.6%)	1,241 (77.1%)	1,151 (62.9%)
Annualized Training (US$)	$2.51	$1.33	$1.85	$2.51	$1.33	$1.85
Personnel & Per Diems (US$)	$3.89	$10.92	$11.00	$0.43	$0.36	$0.44
Test Kits (US$)	$1.00	$3.32	$4.07	$1.00	$3.20	$4.07
Other (US$)	$1.30	$3.16	$3.18	$1.68	$1.68	$1.68
Uptake incentives (US$)**	-	-	$11.04	-	-	$11.04
Total (US$)	US$8.70	US$18.73	US$31.14	US$5.62	US$6.57	US$19.08

* 3 years annualization of capital costs
** includes incentive administration
CONCLUSIONS: Reaching the remaining undiagnosed PLHIV requires innovative strategies and investment. HIVST secondary distribution can increase partner-testing substantially when fully integrated into existing government services. A linkage intervention (incentivized partner return) increased costs considerably.