# SARS-CoV-2 outbreaks in long-term care facilities during the Omicron era in Québec, Canada

## TL;DR

This study examines how SARS-CoV-2 outbreaks in long-term care facilities in Québec, Canada, changed from 2022 to 2024, finding a significant decline in outbreak severity and case fatality rates.

## Contribution

The study provides new insights into the impact of the Omicron era on long-term care facilities, showing reduced outbreak severity and the role of facility size in outbreak likelihood.

## Key findings

- The odds of active outbreaks, case incidence, and case fatality rates significantly decreased during the 2023-24 season compared to 2022.
- Larger facilities (≥40 beds) were more likely to experience outbreaks than smaller ones (10–39 beds).
- Facility bed capacity predicted outbreak occurrence but not the transmission rate within facilities.

## Abstract

Residents of long-term care facilities (LTCFs) are at a high risk of severe COVID-19. Our study analyzed the COVID-19 outbreaks, associated cases and case fatality ratio (CFR) in LTCFs from May-2022 to September-2024 in Québec, Canada. An ecological analysis was conducted including all active LTCFs during the study period (n = 471). Regression analyses using generalized estimating equations were used to model odds of an active COVID-19 outbreak, confirmed COVID-19 cases incidence rate ratio (IRR) and ratio of CFR over different periods (wave 7, 2022-23 season, 2023-24 season), regions and LTCF bed capacity. A total of 2,501 outbreaks were recorded, corresponding to 39,089 COVID-19 cases (among residents and health care workers). The odds of an active outbreak, IRR of COVID-19 cases, and ratio of CFR declined significantly during the 2023-24 season compared to wave 7 (-35%, -39% and -24%, respectively; p-values < 0.0001). While larger LTCFs (≥ 40 beds) were up to 7 times more likely to have an active outbreak vs.10–39 beds, COVID-19 IRR and ratio of CFR were comparable across LTCFs’ bed-capacity. In summary, the burden of COVID-19 on LTCF residents has declined from May 2022 to September 2024. Bed capacity seems to predict outbreak occurrence but not virus transmission within LTCFs.

The online version contains supplementary material available at 10.1038/s41598-025-32967-y.