Summary of findings

The results of our analysis provide an overview of the epidemiology of COVID-19 within LTCFs experiencing outbreaks in the VCH region. Most cases occurred among residents of these facilities, whereas only 1 facility had more COVID-19 cases among staff than residents. Our regression analysis demonstrated that the combination of outbreak control measures (Table 1) delivered through a collaborative approach were associated with a decrease in COVID-19 incidence rates 14 days from implementation in each LTCF. This change from an upward to downward trend in COVID-19 was consistently detected among both staff and residents and across facilities, regardless of the background rates of community transmission. In addition, the impact of the intervention varied between staff and residents, with a significantly greater decrease (level change) in the average rate of COVID-19 among staff compared to residents after the early outbreak period.

Explanation of findings

The pronounced effect of the intervention among staff cases may be attributable to the lower exposure risk experienced by staff because they spend less time in the facility and they use personal protective equipment daily. Also, many of the outbreak control measures are largely focused on rapidly identifying and removing symptomatic staff from the work environment, thereby decreasing the frequency of new COVID-19 introductions into the facility. The gradual but persistent decline of new resident cases after the intervention can be explained by the increased exposure time in the facility as well as challenges with resident isolation (ie, wandering due to cognitive impairment). This pronounced effect among staff is particularly important given that documented infections among staff has been demonstrated to be a strong risk factor of long-term care resident mortality.^{Reference Fisman, Lapointe-Shaw, Bogoch, McCready and Tuite18}

Comparison of related studies in the literature

To the best of our knowledge, this is the first study to evaluate outbreak control measures to mitigate the transmission of COVID-19 in LTCF using a quasi-experimental design. Cheng et al^{Reference Cheng, Wong and Chen19} evaluated a regional infection control response to COVID-19 using descriptive epidemiological methods. Various studies using interrupted time series analysis and segmented regression analysis have evaluated the impact of broader interventions such as social distancing,^{Reference Vokó and Pitter20} travel restrictions,^{Reference Tian, Liu and Li21} and lockdown policies^{Reference Figueiredo, Daponte Codina and Figueiredo22} on COVID-19 incidence and mortality.

In addition, various outbreak summary reports, commentaries, and media articles have highlighted the challenges with managing COVID-19 outbreaks in LTCFs in other regions of Canada, United States, and Europe. Key barriers included poor communication and collaboration between key actors, limited access to personal protective equipment (PPE), inadequate early identification of symptomatic staff and resident cases, and challenges in infection control education and adherence.^{Reference Adlhoch, Kinross and Melidou3,Reference McMichael, Clark and Pogosjans5,Reference Mialkowski6,Reference McMichael, Currie and Clark23-Reference Szczerbińska26} In contrast, our intervention was administered through a collaborative team-based approach that fostered excellent communication between public health and LTCF operators. This approach also facilitated the implementation of public health directives and troubleshooting ongoing concerns with the facility. Working directly within a regional health authority structure, PPE levels were monitored daily and were prioritized to LTCFs facing shortages. Access to accurate resident and staff census lists (through public health licensing officials) allowed early notification, assessment, and exclusion of all symptomatic or significantly exposed staff. Prioritization and low-barrier access to SARS-CoV-2 testing allowed for timely case identification and public health action. Furthermore, our intervention included outbreak measures that have been implemented to curb transmission across the United States, such as cohorting^{Reference Eckardt, Guran and Hennemyre27} and routine symptom monitoring of staff and residents,^{Reference Mills, Kaye and Mody28} universal mask policies,^{Reference Walker, Fleece and Griffin29} appropriate PPE use/ensuring no PPE shortages.^{Reference Telford, Bystrom, Fox, Wiggins-Benn, McCloud, Holland and Shah30} As a result, our analysis provides additional support for the effectiveness of outbreak measures not implemented in large LTCF COVID-19 outbreaks in other jurisdictions and are comparable to recommended approaches in the United States and Canada.^{Reference D’Adamo, Yoshikawa and Ouslander2,Reference Mills, Kaye and Mody28,Reference Chen, Ryskina and Jung31-Reference Ouslander and Grabowski33}

However, important difference exists in our approach compared to what has been reported and recommended in the United States. First, the rapid creation and deployment of a government-funded COVID-19 IPAC outreach team was critical in providing effective standardized^{Reference Mills, Kaye and Mody28} education to staff, carrying out infection control audits, and diminishing a substantial burden on the LTCF IPAC educators and administrators. Also, we did not conduct weekly, biweekly or bimonthly testing of LTCF staff without symptoms, which is currently recommended^{32,Reference Ouslander and Grabowski33} with reported effectiveness.^{Reference Escobar, Lanzi and Saberi34} However, we enacted broad and stringent infection control precautions, which likely reduced the benefit of serial testing.^{Reference Lanièce Delaunay, Saeed and Nguyen35} Lastly, during our study period universal facility-wide testing was not carried out following the first identified case but rather was determined by contact investigations. However, after the conclusion of our study period, the health region has adopted facility-wide testing to align with current evidence.^{Reference Dora, Winnett and Jatt36,Reference Hatfield, Reddy and Forsberg37}

Strengths and limitations

Time-based segmented regression analyses are one of the strongest quasi-experimental designs to evaluate the impact of population-level interventions targeting nosocomial infection rates.^{Reference Shardell, Harris, El-Kamary, Furuno, Miller and Perencevich38} A mixed-effect model also adds rigor to account for dependency (correlation) of observations within each facility. A major strength of a multigroup analysis is the ability to assess for comparability between groups on our observed covariates. Using multiple facilities also increased the number of time points, adding additional power to detect significant effects.^{Reference Bernal, Cummins and Gasparrini12} A time-based approach also allows for the control of overall secular trends in rates, which can provide an estimate of the true impact of the intervention. Our model demonstrated a consistent effect across facilities while accounting for varying COVID-19 incidence rates among facilities and across time. Lastly, LTCFs that experienced significant COVID-19 outbreaks (>2 cases) occurred unsystematically in our region, providing essentially a random sample of LTCFs for analysis.

However, with the study of any model, there are limitations. First, we assumed that the bundle of measures was imposed upon outbreak declaration; however, the actual implementation of each measure may have occurred over a few days, underestimating the true effect of the intervention. Second, although the model evaluates the bundle of measures, it cannot determine the contribution of individual measure to the overall effect nor whether the intervention improved across time as it became more cohesive and comprehensive. Third, our findings should only be generalized to LTCFs experiencing COVID-19 outbreaks (with >2 cases). Our intervention may not be easily implemented or generalizable in jurisdictions that do not utilize a regional health authority structure to deliver health services. Fourth, asymptomatic cases could not be reliably included potentially biasing our results; however, it is unlikely that these cases would significantly drive our final model due to their small size. A final limitation is the lack of a control group (ie, an LTCF where the intervention was not implemented) given that this would have been unethical. Nonetheless, the early outbreak intervention period serves as control for the postintervention period, which still accounts for threats to internal validity and constitutes a methodologically acceptable study design for evaluating the impact of population-level intervention.^{Reference Ansari, Gray and Nathwani39}

In conclusion, our comprehensive, timely intervention leveraged regional partnerships to reduce the incidence of COVID-19 in LTCFs, underscoring the value and importance of collaborative approaches for effective infection control. The findings of this study can help to inform and prepare key policy makers such as public health, infection control practitioners, healthcare professionals, and LTCF operators for future COVID-19 outbreaks. We hope our intervention and its team-based approach can be adapted and utilized by other jurisdictions to effectively decrease SARS-CoV-2 transmission and protect the vulnerable populations in LTCFs.