Healthcare utilization and preventive care among social housing residents compared to the general population during the COVID-19 pandemic in Ontario, Canada: a population-based cohort study.

Introduction: To examine disparities in influenza vaccination and screening for breast, cervical, and colorectal cancers among adults living in social housing compared to the general population of Ontario, Canada, before and during the COVID-19 pandemic. Methods: A population-based cohort study was conducted using linked administrative health data from Ontario, Canada. We studied individuals aged 18 and older who were alive on January 1, 2020. Social housing sites were identified using the 2023 cycle of the Social Housing of Ontario Registry. The complement cohort comprised adults not residing in social housing. Receipt of influenza vaccination and screening for cervical (Pap test), breast (mammography), and colorectal [fecal immunochemical test (FIT)/fecal occult blood test (FOBT)/sigmoidoscopy/colonoscopy] cancers were analyzed using data from the Ontario Breast Screening Program (OBSP), Ontario Cancer Registry (OCR), Ontario Health Insurance Plan (OHIP) Database, and Primary Care Population Database (PCPOP). Age-standardized rates and rate differences between the social housing population and complement cohort were compared for the pre-COVID-19 (2018 and 2019) and COVID-19 (2020 and 2021) periods. Results: The social housing cohort included 297,644 individuals, while the complement cohort had 11,386,078 individuals. The social housing cohort had higher proportions of older adults (≥60 years) and females. Age- and sex-standardized disparities in influenza vaccination (≥1 dose in 2-year period) between social housing residents and the complement cohort widened during the COVID-19 pandemic from -0.30 to -1.84%, with the largest gaps observed among adults aged 80 and older. While age- and sex-standardized disparities in breast and cervical cancer screening narrowed, they remained significant. In contrast, the age- and sex-standardized disparity in colorectal cancer screening increased from -7.42 to -9.69%, particularly among males and older adults aged 60-74. Discussion: Disparities in healthcare utilization and preventive care between social housing residents and the complement cohort persisted or widened during the COVID-19 pandemic, most notably for influenza vaccination and colorectal cancer screening. Narrowing of some screening disparities was primarily attributed to overall declines in screening rates rather than improved access. These findings emphasize the need for targeted, equity-focused public health strategies to improve access to preventive healthcare services for socially and economically disadvantaged populations.