Evaluating the safety and immunogenicity of SARS-CoV-2 vaccines among underserved urban populations with intersecting risk factors for COVID-19 morbidity and mortality: a pooled analysis of three prospective cohort studies in Vancouver, Canada [SIC19VUUP, study data contributed to the CITF Databank]

<b>Background:</b> In Canada, urban centers have a high prevalence of vulnerable populations with increased risk factors for COVID-19, including homelessness, living in group settings, high-intensity substance use, and infectious diseases, who face many barriers to healthcare services. The uptake, safety, and effectiveness of COVID-19 vaccinations have not been studied in these populations yet. <br>

<b>Aims of the CITF funded study:</b> This study aimed to 1) analyze the effectiveness of COVID-19 vaccines among different groups within vulnerable populations, 2) evaluate vaccine uptake and adherence to vaccine protocols, and 3) evaluate vaccines’ length of effectiveness against infection and any potential side effects. <br>

<b>Methods:</b> This study enrolled participants in 3 cohorts across Vancouver, British Columbia: individuals from the Vancouver Injection Drug Users Study (VIDUS) who were 18 years or older, HIV negative, and past-30-day injection drug use, individuals from the AIDS Care Cohort (ACCESS) who were 18 years or older, HIV seropositive, and past-30-day injection/non-injection drug use, and individuals from the At-Risk Youth Study (ARYS) who were between 14 and 26 years old, “street-involved” (precariously housed or homeless), and past-30-day injection drug use. All participants were zero, partially, or fully vaccinated against COVID-19. Participants from each cohort answered a questionnaire and provided blood samples via dried blood spot and venipuncture at baseline, and at follow ups 2-months, 4- months, and 6-months post vaccination. <br>

<b>Contributed dataset contents:</b> The datasets include 275 participants who completed baseline surveys between June 2021 and September 2021. 101 participants came from the VIDUS cohort, 97 from ACCESS, and 77 from ARYS. All participants gave one or more blood samples at baseline, and approximately 93% gave additional samples at follow ups between September 2021 and March 2022. A total of 1223 samples were collected. Variables include data in the following areas of information: demographics (age, gender, ethnicity, household composition, occupation), general health (weight and height, smoking, chronic conditions, flu vaccine), longitudinal follow-up for COVID infection (dates of positive tests, symptoms, hospitalizations), SARS-CoV-2 vaccination, and serology (IgG against SARS-CoV-2 RBD, nucleocapsid, and spike proteins).