Care-home outbreaks of COVID-19 in Scotland March to May 2020: National linked data cohort analysis

Abstract

Background understanding care-home outbreaks of COVID-19 is a key public health priority in the ongoing pandemic to help protect vulnerable residents. Objective to describe all outbreaks of COVID-19 infection in Scottish care-homes for older people between 01/03/2020 to 31/03/2020, with follow-up to 30/06/2020. Design and setting national linked data cohort analysis of Scottish care-homes for older people. Methods data linkage was used to identify outbreaks of COVID-19 in care-homes. Care-home characteristics associated with the presence of an outbreak were examined using logistic regression. Size of outbreaks was modelled using negative binomial regression. Results 334 (41%) Scottish care-homes for older people experienced an outbreak, with heterogeneity in outbreak size (1–63 cases; median = 6) and duration (1–94 days; median = 31.5 days). Four distinct patterns of outbreak were identified: ‘Typical’ (38% of outbreaks, mean 11.2 cases and 48 days duration), Severe (11%, mean 29.7 cases and 60 days), Contained (37%, mean 3.5 cases and 13 days), and Late-onset (14%, mean 5.4 cases and 17 days). Risk of a COVID-19 outbreak increased with increasing care-home size (for ≥90 beds vs <20, adjusted OR = 55.4, 95%CI 15.0–251.7) and rising community prevalence (OR = 1.2 [1.0–1.4] per 100 cases/100,000 population increase). No routinely available care-home characteristic was associated with outbreak size. Conclusions reducing community prevalence of COVID-19 infection is essential to protect those living in care-homes. More systematic national data collection to understand care-home residents and the homes in which they live is a priority in ensuring we can respond more effectively in future.

COVID-19 in Scottish care homes: A metapopulation model of spread among residents and staff

“…To mitigate the effect of the differing variance of the data sets, we shifted the four time-series to the same scale, this being weekly cases/deaths. The size of individual care homes is believed to be the main factor that influences the likelihood of a care home outbreak [14,20,41]. Larger homes typically have more staff and therefore a higher chance of experiencing outbreak before the smaller ones.…”

“…The size of individual care homes is believed to be the main factor that influences the likelihood of a care home outbreak [14, 20, 42]. Larger homes typically have more staff and therefore a higher chance of experiencing an outbreak before the smaller ones.…”

Epidemiology of SARS-CoV-2 during the first three waves in Scotland: a national record linkage study

“…In addition, a spread into care homes was seen in Scotland prior to the initial UK-wide lockdown in March 2020. 28 As the average age of Scotland’s care home population in 2019 was 82 years, 29 outbreaks observed here may also have contributed to the older age of detected cases in wave 1, alongside differences in disease severity and vaccination coverage as previously discussed. At the same time, national lockdown and closure of educational establishments meant younger age groups were less likely to be exposed to SARS-CoV-2.…”

Usefulness of linked data for infectious disease events: a systematic review

“…The cohort study design was most common ( n = 38, 70.4%) [ 8 , 35 – 53 , 55 , 57 – 59 , 61 – 66 , 68 – 71 , 74 , 77 , 81 , 82 ]. Five studies were descriptive analyses [ 54 , 56 , 60 , 78 , 80 ], three were case-control studies [ 72 , 85 , 89 ] and two studies used capture-recapture analysis [ 75 , 76 ]. One study was a sensitivity calculation for a surveillance system [ 84 ].…”