Time-to-completion of COVID-19 vaccination primary series varies by HIV viral load status among people who inject drugs in Baltimore, Maryland.

People who inject drugs (PWID) may have diminished access to essential preventive services like COVID-19 vaccination given structural and substance use barriers. We aimed to assess the role of HIV on COVID-19 vaccination uptake among adult PWID participating in the ALIVE cohort study in Baltimore, Maryland who were alive as of April 2021. We abstracted COVID-19 vaccination data from electronic medical records via the regional health information exchange. We used Kaplan-Meier method to estimate time from universal vaccine eligibility (April 6, 2021) to completion of the COVID-19 vaccination primary series (1 dose J&J or 2 doses mRNA) by HIV viral load status (uninfected, PWH [HIV-RNA < 400 copies/mL], PWH [HIV-RNA ≥ 400 copies/mL]) and Cox Proportional Hazards regression to adjust for potential confounders. Our sample (N = 960) was primarily black (77%) and male (65%) with 31% reporting recent injection drug use. Among 265 (27%) people living with HIV (PWH) in our sample, 84% were virally suppressed. As of February 22, 2022, 539 (56%) completed the primary series, 131 (14%) received a single dose of mRNA vaccine and 290 (30%) remained unvaccinated. Compared to PWID without HIV, virally suppressed PWH were more likely to complete the primary series (Adjusted Hazard Ratio [aHR]:1.23,95% Confidence Interval [95 %CI]:1.07,1.50), while PWH who were not virally suppressed were less likely (aHR:0.72,95 %CI:0.45,1.16), although this was not statistically significant. We conclude that among PWID, HIV infection and viral suppression is associated with quicker vaccination uptake, likely due to HIV care engagement. Targeted improvements along the HIV care continuum may bolster vaccine uptake.