This explanatory sequential mixed methods hybrid Type 1 study examined the efficacy and implementation of Connect2Test, a brief motivational enhancement intervention to increase SARS-CoV-2 testing among people experiencing houselessness and people who inject drugs. We conducted a randomized controlled trial with participants randomly assigned to Connect2Test (n = 105) or services as usual (n = 100). Most participants self-identified as male (65%), White (72%), and not Hispanic (87%). There were no intervention effects on immediate testing rates, χ²(1, n = 205) = 0.23, p = .6298, OR [95% CI] = 1.18 [0.61, 2.27], or at 1-month, χ²(1, n = 205) = 0.05, p = .8263, OR [95% CI] = 0.93 [0.51, 1.72], or 2-month follow-ups, χ²(1, n = 205) = 0.04, p = .8368, OR [95% CI] = 1.08 [0.52, 2.22]. We interviewed staff and volunteers (n = 17) affiliated with our community partner to examine implementation barriers and facilitators. Barriers included (a) intervention complexity, (b) no established relationship between the interventionist and participants, (c) Connect2Test's misalignment with priorities of people experiencing houselessness, and (d) incompatibility with community partner resources. Facilitators included (a) congruency between motivational interviewing and harm reduction values, (b) collaboration with a trusted community partner, and (c) intervention alignment with the community partner's mission. Although Connect2Test did not increase testing rates, our qualitative assessment highlighted barriers reflecting intervention and implementation failure. Facilitators highlighted Connect2Test adaptations to enhance efficacy. Juxtaposing qualitative implementation assessments with randomized controlled trials can discern implementation and intervention factors impacting efficacy to inform redesign. (PsycInfo Database Record (c) 2025 APA, all rights reserved).
Trial registration: ClinicalTrials.gov NCT04852848.