Epidemiology and clinical features of COVID-19 outbreaks in aged care facilities: A systematic review and meta-analysis

Abstract

Background: COVID-19 outbreaks in aged care facilities (ACFs) often have devastating consequences. However, epidemiologically these outbreaks are not well defined. We aimed to define such outbreaks in ACFs by systematically reviewing literature published during the current COVID-19 pandemic.

Methods: We searched 11 bibliographic databases for literature published on COVID-19 in ACFs between December 2019 and September 2020. Original studies reporting extractable epidemiological data as part of outbreak investigations or non-outbreak surveillance of ACFs were included in this systematic review and meta-analysis. PROSPERO registration: CRD42020211424.

Findings: We identified 5,148 publications and selected 49 studies from four continents reporting data on 214,380 residents in 8,502 ACFs with 25,567 confirmed cases of COVID-19. Aged care residents form a distinct vulnerable population with single-facility attack rates of 45% [95% CI 32-58%] and case fatality rates of 23% [95% CI 18-28%]. Of the cases, 31% [95% CI 28-34%] were asymptomatic. The rate of hospitalization amongst residents was 37% [95% CI 35-39%]. Data from 21 outbreaks identified a resident as the index case in 58% of outbreaks and a staff member in 42%. Findings from the included studies were heterogeneous and of low to moderate quality in risk of bias assessment.

Interpretation: The clinical presentation of COVID-19 varies widely in ACFs residents, from asymptomatic to highly serious cases. Preventing the introduction of COVID-19 into ACFs is key, and both residents and staff are a priority group for COVID-19 vaccination. Rapid diagnosis, identification of primary and secondary cases and close contacts plus their isolation and quarantine are of paramount importance.

Funding: Queensland Advancing Clinical Research Fellowship awarded to Prof. Gulam Khandaker by Queensland Health's Health Innovation, Investment and Research Office (HIRO), Office of the Director-General.

Keywords: Aged care facility; Clinical features; Coronavirus disease 2019; Covid-19; Epidemiology; Nursing homes; Outbreak; SARS-CoV-2.

Fig. 1

Flow diagram of the study selection process.

Fig. 2

Global distribution of the included studies by country.

Fig. 3

Forest plot of the attack rate of residents in aged care homes Horizontal lines represent the 95% CIs around the point estimates for each study, and the grey shaded areas are proportional to the weight given to each study.

Fig. 4a

Forest plot of the case fatality rate of residents in aged care homes (all studies). Horizontal lines represent the 95% CIs around the point estimates for each study, and the grey shaded areas are proportional to the weight given to each study.

Fig. 4b

Forest plot of the case fatality rate of residents in aged care homes (single-centre studies). Horizontal lines represent the 95% CIs around the point estimates for each study, and the grey shaded areas are proportional to the weight given to each study.

Fig. 5

Funnel plot of publication bias based on the pooled attack rate and case fatality rate. The upper-left funnel plot shows the publication bias for all studies; the upper-right funnel plot shows the bias for studies reporting outbreaks in a single centre; the middle-left funnel plot shows the bias for all studies reporting a case fatality rate; the middle-right funnel plot shows the bias for case fatality rates from single-centre outbreaks. the lower-left funnel plot shows the bias for all studies reporting mortality rate; the middle-right funnel plot shows the bias for mortality rates from single-centre outbreaks. Red diamond: large multi-facility reports; blue diamond: medium-sized multi-facility reports; black: single-centre reports. x-axis=proportion, y-axis=sampling variance.