A Brief Peer-Led Intervention to Increase COVID-19 Vaccine Uptake Among People Who Inject Drugs in San Diego County: Results From a Pilot Randomized Controlled Trial

BACKGROUND: We evaluated the impact of a brief peer-led intervention on COVID-19 vaccination among people who inject drugs (PWID) presenting at syringe services program (SSP) locations in San Diego County, California. METHODS: Between March and July 2022, PWID aged ≥18 years without recent voluntary COVID-19 testing who were not up to date on COVID-19 vaccinations received a single-session motivational interviewing intervention (LinkUP) or an attention-matched didactic control condition from trained peer counselors at SSP sites randomized by week. Following either 30-minute session, counselors offered referrals to local vaccination services. Multivariable log binomial regression via generalized estimating equations assessed LinkUP effects on (1) acceptance of COVID-19 vaccination referrals immediately postintervention and (2) COVID-19 vaccine uptake at 6-month follow-up. RESULTS: COVID-19 vaccination outcomes were obtained on 135 (90.6%) of 149 participants. In multivariable analysis, participants receiving LinkUP had greater acceptance of COVID-19 vaccination referrals than controls (adjusted relative risk, 3.50; 95% CI, 1.01–12.2) and were marginally more likely to report receiving a new COVID-19 vaccine dose (adjusted relative risk, 1.57; 95% CI, .99–2.48). After 6 months, 20% reported receiving a new vaccine dose; however, if COVID-19 vaccine had been available at SSPs, this proportion could have been as high as 34.3% (45.3% LinkUP vs 24.3% control; P = .01). CONCLUSIONS: A brief peer-led SSP-based intervention significantly improved COVID-19 vaccination among PWID. Further improvements could likely be obtained by supporting SSPs to offer COVID-19 vaccination on-site instead of relying on referrals. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov NCT05181657.