ABSTRACT
Background A defining feature of the COVID-19 pandemic in many countries was the tragic extent to which care home residents were affected, and the difficulty preventing introduction and subsequent spread of infection. Management of risk in care homes requires good evidence on the most important transmission pathways. One hypothesised route at the start of the pandemic, prior to widespread testing, was transfer of patients from hospitals, which were experiencing high levels of nosocomial events. Methods We tested the hypothesis that hospital discharge events increased the intensity of care home cases using a national individually linked health record cohort in Wales, UK. We monitored 186,772 hospital discharge events over the period March to July 2020, tracking individuals to 923 care homes and recording the daily case rate in the homes populated by 15,772 residents. We estimated the risk of an increase in cases rates following exposure to a hospital discharge using multi-level hierarchical logistic regression, and a novel stochastic Hawkes process outbreak model. Findings In regression analysis, after adjusting for care home size, we found no significant association between hospital discharge and subsequent increases in care home case numbers (odds ratio: 0.99, 95% CI 0.82, 1.90). Risk factors for increased cases included care home size, care home resident density, and provision of nursing care. Using our outbreak model, we found a significant effect of hospital discharge on the subsequent intensity of cases. However, the effect was small, and considerably less than the effect of care home size, suggesting the highest risk of introduction came from interaction with the community. We estimated approximately 1.8% of hospital discharged patients may have been infected. Interpretation There is growing evidence in the UK that the risk of transfer of COVID-19 from the high-risk hospital setting to the high-risk care home setting during the early stages of the pandemic was relatively small. Although access to testing was limited to initial symptomatic cases in each care home at this time, our results suggest that reduced numbers of discharges, selection of patients, and action taken within care homes following transfer all may have contributed to mitigation. The precise key transmission routes from the community remain to be quantified.
Subject(s)
COVID-19ABSTRACT
Background: Adult residential and nursing care homes are settings in which older and often vulnerable people live in close proximity. This population experiences a higher proportion of respiratory and gastrointestinal illnesses than the general population and has been shown to have a high morbidity and mortality in relation to COVID-19.Methods: We examined 3,115 hospital discharges to 1,068 Welsh adult care homes and the subsequent outbreaks of COVID-19 occurring over an 18 week period between 22 February and 27 June 2020. A Cox proportional hazards regression model was used to assess the impact of time-dependent exposure to hospital discharge on the incidence of the first known outbreak, over a window of 7-21 days after discharge, and adjusted for care home characteristics, including size, type of provision and health board.Results: A total of 330 homes experienced an outbreak of COVID-19, and 544 homes received a discharge from hospital over the study period. The exposure to discharge from hospital was not associated with a significant increase in the risk of a new outbreak (hazard ratio 1·15, 95% CI 0·89, 1·47, p = 0.29) after adjusting for care home characteristics. Care home size was by far the most significant predictor. Hazard ratios (95% CI) in comparison to homes of <10 residents were: 3·40 (1·99, 5·80) for 10-24 residents; 8·25 (4·93, 13·81) for 25-49 residents; and 17·35 (9·65, 31·19) for homes of 50+ residents. When stratified for care home size, the outbreak rates were similar for periods when homes were exposed to a hospital discharge, in comparison to periods when homes were unexposed.Conclusion: Our analyses showed that large homes were at considerably greater risk of outbreaks throughout the epidemic, and after adjusting for care home size, a discharge from hospital was not associated with a significant increase in risk.Funding Statement: No specific funding was sought or provided for this work.Declaration of Interests: None declared.Ethics Approval Statement: This analysis was carried out as part of the ongoing response to the Covid-19 epidemic in Wales, under the governance of the Public Health Wales Incident Management Team, so ethical approval was not required.
Subject(s)
COVID-19 , Encephalitis, Arbovirus , Alzheimer DiseaseABSTRACT
BackgroundAdult residential and nursing care homes are settings in which older and often vulnerable people live in close proximity. This population experiences a higher proportion of respiratory and gastrointestinal illnesses than the general population and has been shown to have a high morbidity and mortality in relation to COVID-19. MethodsWe examined 3,115 hospital discharges to 1,068 Welsh adult care homes and the subsequent outbreaks of COVID-19 occurring over an 18 week period between 22 February and 27 June 2020. A Cox proportional hazards regression model was used to assess the impact of time-dependent exposure to hospital discharge on the incidence of the first known outbreak, over a window of 7-21 days after discharge, and adjusted for care home characteristics, including size, type of provision and health board. ResultsA total of 330 homes experienced an outbreak of COVID-19, and 544 homes received a discharge from hospital over the study period. The exposure to discharge from hospital was not associated with a significant increase in the risk of a new outbreak (hazard ratio 1{middle dot}15, 95% CI 0{middle dot}89, 1{middle dot}47, p = 0{middle dot}29) after adjusting for care home characteristics. Care home size was by far the most significant predictor. Hazard ratios (95% CI) in comparison to homes of <10 residents were: 3{middle dot}40 (1{middle dot}99, 5{middle dot}80) for 10-24 residents; 8{middle dot}25 (4{middle dot}93, 13{middle dot}81) for 25-49 residents; and 17{middle dot}35 (9{middle dot}65, 31{middle dot}19) for homes of 50+ residents. When stratified for care home size, the outbreak rates were similar for periods when homes were exposed to a hospital discharge, in comparison to periods when homes were unexposed. ConclusionOur analyses showed that large homes were at considerably greater risk of outbreaks throughout the epidemic, and after adjusting for care home size, a discharge from hospital was not associated with a significant increase in risk. Research in contextO_ST_ABSWhat is already known on this subjectC_ST_ABSO_LICare home populations experience more respiratory outbreaks than the general population1 and older people have been more severely affected by COVID-19, with a case fatality proportion of 2{middle dot}3% overall but 8% in those aged 70-79 and 14{middle dot}8% in those aged over 802 C_LIO_LIEvidence and modelling suggested that up to half of all COVID-19 fatalities could come from the care home population3 and that testing prior to hospital discharge was not always available or undertaken9 C_LIO_LIType and use of PPE6 and the number of staff employed can have an impact on care home outbreaks of COVID-196,7 C_LI What this study addsO_LIOur analysis found no effect of hospital discharges on care home outbreaks once care home size had been adjusted for. In line with previous studies, larger care homes were much more likely to experience an outbreak C_LI