Colocation of COVID-19 Vaccination Services at Syringe Service Programs for People Who Inject Drugs and People Experiencing Houselessness in Oregon

Objectives: Integrating vaccination services with other essential health services could increase vaccination rates among socially marginalized populations. We examined the associations between colocation of vaccines at syringe service programs and COVID-19 vaccination status among people who inject drugs and people experiencing houselessness. Methods: This study included 1891 participants aged >= 18 years at 9 sites in Oregon from July 2021 through March 2022. Participants self-reported whether they had ever received >= 1 dose of a COVID-19 vaccine. We calculated site-level COVID-19 vaccine availability and overall vaccination rates. We compared site-level vaccination rates and analyzed the association between vaccine availability and vaccination status. Results: We found no significant difference in vaccination rates between sites that did and did not offer COVID-19 vaccines (t(7) = -0.33; P = .75). We also found no significant association between vaccine availability and vaccination status. However, the odds of having received a COVID-19 vaccine were 2.79 times higher for each additional site visit during which COVID-19 vaccines were available (odds ratio [OR] = 2.79; 95% CI, 2.18-3.58; P < .001). The association between vaccine availability and vaccine status was not moderated by participant age (OR = 1.03; 95% CI, 0.99-1.07; P = .13) or housing instability (OR = 0.59; 95% CI, 0.13-2.60; P = .48). Conclusions: Colocating COVID-19 vaccines at syringe service programs was only positively associated with vaccination status if vaccines were offered frequently on-site. Future work should examine whether the frequency of offering vaccination services increases willingness to engage in vaccination and examine trust and convenience as potential mechanisms.