Optimizing COVID-19 surveillance in long-term care facilities: a modelling study

Abstract

Background: Long-term care facilities (LTCFs) are particularly vulnerable to nosocomial outbreaks of coronavirus disease 2019 , with high rates of transmission and mortality. Timely epidemiological surveillance is essential to detect and respond to outbreaks, but testing resources are highly limited in the current pandemic context. Methods:We used an individual-based transmission model to simulate COVID-19 spread along interindividual contact networks in the LTCF setting. A range of surveillance strategies were evaluated for their ability to detect simulated outbreaks, assuming limited availability of standard RT-PCR tests. Various epidemiological scenarios were considered, including COVID-19 importation from patient transfers or staff members infected in the community. Findings:We estimated a median delay of 7 (95% uncertainty interval: 2-15) days from importation of an asymptomatic COVID-19-infected patient to first presentation of COVID-19 symptoms among any patients or staff, at which point an additional 7 (0-25) individuals were infected but did not (yet) show symptoms. Across a range of scenarios, the reference surveillance strategy (testing individuals with COVID-like symptoms with signs of severity) took a median 11-21 days to detect an outbreak. Group testing (pooling specimens from multiple individuals for a single RT-PCR test) patients and staff with any COVID-like symptoms was both the most timely and efficient strategy, detecting outbreaks up to twice as quickly as the reference, and more quickly than other considered strategies while using fewer tests. Maximizing use of available tests via testing cascades was more effective . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) and containing the terms ("COVID" OR "coronavirus" OR "nCoV" OR "SARS-CoV-2) AND ("long-term care" OR "LTCF"). We identified 16 articles published in academic journals, mostly outbreak reports and editorials describing a need for improved testing and control measures. Very few of the 179 identified preprints were studies of COVID-19 in long-term care. A separate search for the same COVID terms AND ("transmission model" OR "mathematical model" OR "dynamic model") returned 29 published articles, including an evaluation of surveillance strategies in airports, and a range of transmission models at the country or community levels, but none specifically tailored to healthcare settings, whether hospitals, LTCFs or otherwise. Among 776 preprints, we identified a large number of studies assessing and projecting COVID-19 burden in hospital systems, but only two transmission models specific to healthcare settings, neither of which addressed long-term care settings nor options for epidemiological surveillance. Together, this suggests a lack of research on the unique transmission dynamics and surveillance considerations for COVID-19 in healthcare settings. This gap is further highlighted by ex...

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