Shielding residents in care homes is not as effective as previously predicted in a number of studies.
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Maintaining a low risk of transmission per contact helps reduce the effect of relaxing visitation.
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Cohorting of residents and staff reduces the spread of COVID-19.
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The risk of outbreak occurrence in a care home is associated with its population size.
Abstract
Background
This study examines the impact of visitation and cohorting policies as well as the care home population size upon the spread of COVID-19 and the risk of outbreak occurrence in this setting.
Methods
Agent-based modelling
Results
The likelihood of the presence of an outbreak in a care home is associated with the care home population size. Cohorting of residents and staff into smaller, self-contained units reduces the spread of COVID-19. Restricting the number of visitors to the care home to shield its residents does not significantly impact the cumulative number of infected residents and risk of outbreak occurrence in most scenarios. Only when the community prevalence where staff live is considerably lower than the prevalence where visitors live (the former prevalence is less than or equal to 30% of the latter), relaxing visitation increases predicted infections much more significantly than it does in other scenarios. Maintaining a low infection probability per resident-visitor contact helps reduce the effect of allowing more visitors into care homes.
Conclusions
Our model predictions suggest that cohorting is effective in controlling the spread of COVID-19 in care homes. However, according to predictions shielding residents in care homes is not as effective as predicted in a number of studies that have modelled shielding of vulnerable population in the wider communities.
Key Words
Long term care
Care homes
COVID-19
Visitation
Cohorting
Agent-based models
Cited by (0)
Funding: University Research Excellence Award (REA) Studentship.
Conflicts of interests: We declare that all authors have no conflict of interest.
Contributors: LN, IM, and SH designed the model and planned the inference framework. LN programmed the model, performed data analysis, interpreted the study findings with help from IM and SH. LN wrote the first manuscript, and IM and SH contributed to commenting on and editing the subsequent versions of the manuscript. DM and SP provided relevant data on COVID-19 spread and infection control policies in care homes in Lanarkshire and contributed to designing the examined interventions and verifying the model design. DM, SP, RV, and GA facilitated the communication between LN and other care home stakeholders for data collection. All authors contributed to scoping the problems and approving the work and final version of the manuscript for publication.
