Factors impacting resident outcomes from COVID-19 outbreaks in Residential Aged Care Facilities in Sydney Local Health District: testing an infection prevention and control scoring system

BACKGROUND: COVID-19 outbreaks have disproportionately affected Residential Aged Care Facilities (RACFs) around the world, with devastating impacts for residents and their families. Many factors such as community prevalence, facility layout, and infection control practices have been linked to resident outcomes. At present, there are no scoring systems designed to quantify these factors and assess their level of association with resident attack rates and mortality rates. METHODS: We constructed a novel Infection Prevention and Control (IPC) scoring system to quantify facility layout, ability to cohort residents, and IPC practices in RACFs. We conducted a retrospective observational cohort study of COVID-19 outbreaks, applying our IPC scoring system to all COVID-19 outbreaks occurring in RACFs in Sydney Local Health District during the Delta and Omicron waves of the COVID-19 pandemic in New South Wales, Australia. RESULTS: Twenty-six COVID-19 outbreaks in 23 facilities in the Delta wave, and 84 outbreaks in 53 facilities in the Omicron wave were included in the study. A linear Generalised Estimating Equation model was fitted to the Omicron data. Higher IPC scores were associated with higher attack rates and mortality rates. Facilities with IPC scores greater than 75.0% had attack rates 19.6% higher [95% CI: 6.4%-32.8%] and mortality rates 1.7% higher [95% CI: 0.6%-2.7%] than facilities with an IPC score of less than 60.0%. CONCLUSIONS: The results of this study suggest the utility of the IPC scoring system for identifying facilities at greater risk of adverse outcomes from COVID-19 outbreaks. While further validation and replication of accuracy is required, the IPC scoring system could be used and adapted to improve planning, policy, and resource allocation for future outbreaks. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-023-16634-3.