AUTHOR=Richard Lucie , Holland Anna , Aghanya Vivian , Campitelli Michael A. , Hwang Stephen W. 

TITLE=Uptake of COVID-19 vaccination among community-dwelling individuals receiving healthcare for substance use disorder and major mental illness: a matched retrospective cohort study

JOURNAL=Frontiers in Public Health

VOLUME=Volume 12 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2024.1426152

DOI=10.3389/fpubh.2024.1426152

ISSN=2296-2565

ABSTRACT=Patients with major mental illness (MMI) and substance use disorders (SUD) face barriers to accessing health care. In this population-based retrospective cohort study conducted in Ontario, Canada, we investigated the uptake of COVID-19 vaccination among community-dwelling individuals receiving healthcare for major mental illness (MMI) and/or substance use disorders (SUD), comparing them to matched general population controls. Using linked health administrative data, we identified 337,290 individuals receiving healthcare for MMI and/or SUD as of December 14, 2020, matched by age, sex, and residential geography to controls without such healthcare. Follow-up extended until December 31, 2022, to capture vaccination events. Overall, individuals receiving healthcare for MMI and/or SUD (N=337,290) had slightly lower uptake of first (Cumulative incidence 82.45% vs 86.44%; Hazard ratio [HR] 0.83 [95% CI 0.82-0.83]) and second dose (78.82% vs 84.93%; HR 0.77 [95% CI 0.77-0.78]) compared to matched controls. Individuals receiving healthcare for MMI only (n=146,399) had similar uptake of first (87.96% vs. 87.59%; HR 0.97 [95% CI 0.96-0.98]) and second dose uptake (86.09% vs. 86.05%, HR 0.94 [95% CI 0.93-0.95]). By contrast, individuals receiving healthcare for  SUD only (n=156,785) or MMI and SUD (n=34,106) had significantly lower first (SUD 78.14% vs. 85.74%; HR 0.73 [95% CI 0.72-0.73]; MMI & SUD 78.43% vs 84.74%; HR 0.76 [95% CI 0.75-0.77]) and second dose uptake (SUD 73.12% vs. 84.17%; HR 0.66 [95% CI 0.65-0.66]; MMI & SUD 73.48% vs. 82.93%; HR 0.68 [95% CI 0.67-0.69]). These findings suggest that effective strategies to increase future COVID-19 and other emerging infectious disease vaccination uptake among community-dwelling people with SUD are needed.