Facility- and ward-level factors associated with SARS-CoV-2 outbreaks among residents in long-term care facilities: A retrospective cohort study

Objectives: Long-term care facilities (LTCFs) have been disproportionately impacted by COVID-19. Yet, the reasons why certain LTCFs are affected more by outbreaks are poorly understood. This study aimed to identify the facility- and ward-level factors associated with SARS-CoV-2 outbreaks among LTCF residents. Methods: We conducted a retrospective cohort study of multiple Dutch LTCFs (N = 60; with 298 wards providing care for ∼5600 residents) from September 2020 to June 2021. A dataset was constructed linking SARS-CoV-2 cases among LTCF residents to facility- and ward-level factors. Multilevel logistic regression analyses examined the associations between these factors and the likelihood of a SARS-CoV-2 outbreak among residents. Results: During periods of the Classic variant, the mechanical recirculation of air was associated with significantly increased odds of a SARS-CoV-2 outbreak. During periods of the Alpha variant, the factors associated with significantly increased odds included large ward size (≥21 beds), wards providing psychogeriatric care, fewer restrictions on staff movement between wards and facilities, and a greater number of cases among staff (>10 cases). Conclusion: Policy and protocols on reducing resident density, staff movement, and mechanical recirculation of air in buildings are recommended to enhance outbreak preparedness in LTCFs. The implementation of low-threshold preventive measures among psychogeriatric residents is important because they appear as a particularly vulnerable group.