Table 1. Study aims and hypotheses.

Aim	Description	Hypothesis
Aim 1: Reach	Characterize HIV risk factors among veterans who obtained ≥1 VMa-dispensed HIVSTb.	Among survey respondents, commonly reported HIV risk indicators will include male-to-male sexual contact, condomless sex, and unregulated drug use in the past 6 months.
Aim 2: Effectiveness (early outcomes; not causal)	Describe early, self-reported outcomes after obtaining a VM-dispensed HIVST (eg, intended use, completed use, results, and planned next steps) and the perceived usefulness of embedded HIV resources.	Most participants will report intending to use or having used the HIVST, will report reviewing the included post-test resources, and will report an intention to seek confirmatory testing and/or prevention services (eg, HIV pre-exposure prophylaxis).
Aim 3: Adoption	Identify which VM locations have the highest HIVST dispensing volume and when dispensing occurs (eg, clinic vs supportive housing; weekday vs after hours).	HIVST dispensing will be the highest at locations with higher baseline VM utilization and/or higher concentration of veterans experiencing housing instability (eg, supportive housing sites or outpatient clinics serving veterans experiencing homelessness).
Aim 4: Implementation and Maintenance	Assess implementation outcomes (eg, direct costs) and acceptability/experience of veterans with VM-dispensed HIVST (eg, convenience, privacy, satisfaction, and preference compared with other access points).	Participants will rate the VM delivery method as highly acceptable (eg, convenient, private, and satisfactory) and will describe VM access as a low-barrier, low-stigma option for obtaining HIV testing; dispensing will be feasible to maintain over the pilot period with measurable restocking workflows.

^aVM: vending machine.

^bHIVST: HIV self-test.