Preliminary Efficacy of a Theory-Informed Intervention to Increase COVID-19 Testing Uptake Among People Who Inject Drugs in San Diego County: Findings From a Pilot Randomized Controlled Trial.

People who inject drugs (PWID) are vulnerable to severe COVID-19 disease yet have low rates of COVID-19 testing. We partnered with a syringe service program (SSP) in San Diego County, CA, to develop "LinkUP," an evidence- and community-informed intervention. Specifically, LinkUP used tailored education, motivational interviewing, and problem-solving and planning strategies to increase COVID-19 testing uptake among PWID. This study was a pilot randomized controlled trial (RCT) designed to assess the preliminary efficacy of LinkUP in increasing PWID COVID-19 testing. We referred participants (PWID, ≥18 years old, San Diego residents without recent voluntary COVID-19 testing) to mobile SSP sites that had been randomized (by week). Trained peer counselors then offered LinkUP or an educational control condition lasting the same length (~30 minutes). After either condition, counselors offered on-site rapid COVID-19 antigen testing. Among 150 participants, our analyses found that the LinkUP intervention was associated with higher COVID-19 testing uptake, especially for participants experiencing homelessness. In summary, our findings from this pilot RCT support the preliminary efficacy of the "LinkUP" intervention in increasing COVID-19 testing among PWID. This study also underscores the importance of academic-community partnerships and prevention service delivery through SSPs and other community-based organizations serving vulnerable populations.