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Runge M, Richardson RAK, Clay PA, Bell A, Holden TM, Singam M, Tsuboyama N, Arevalo P, Fornoff J, Patrick S, Ezike NO, Gerardin J. Modeling robust COVID-19 intensive care unit occupancy thresholds for imposing mitigation to prevent exceeding capacities. PLOS Glob Public Health 2022; 2:e0000308. [PMID: 36962179 PMCID: PMC10021999 DOI: 10.1371/journal.pgph.0000308] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/09/2022] [Indexed: 12/15/2022]
Abstract
In non-pharmaceutical management of COVID-19, occupancy of intensive care units (ICU) is often used as an indicator to inform when to intensify mitigation and thus reduce SARS-CoV-2 transmission, strain on ICUs, and deaths. However, ICU occupancy thresholds at which action should be taken are often selected arbitrarily. We propose a quantitative approach using mathematical modeling to identify ICU occupancy thresholds at which mitigation should be triggered to avoid exceeding the ICU capacity available for COVID-19 patients and demonstrate this approach for the United States city of Chicago. We used a stochastic compartmental model to simulate SARS-CoV-2 transmission and disease progression, including critical cases that would require intensive care. We calibrated the model using daily COVID-19 ICU and hospital census data between March and August 2020. We projected various possible ICU occupancy trajectories from September 2020 to May 2021 with two possible levels of transmission increase and uncertainty in core model parameters. The effect of combined mitigation measures was modeled as a decrease in the transmission rate that took effect when projected ICU occupancy reached a specified threshold. We found that mitigation did not immediately eliminate the risk of exceeding ICU capacity. Delaying action by 7 days increased the probability of exceeding ICU capacity by 10-60% and this increase could not be counteracted by stronger mitigation. Even under modest transmission increase, a threshold occupancy no higher than 60% was required when mitigation reduced the reproductive number Rt to just below 1. At higher transmission increase, a threshold of at most 40% was required with mitigation that reduced Rt below 0.75 within the first two weeks after mitigation. Our analysis demonstrates a quantitative approach for the selection of ICU occupancy thresholds that considers parameter uncertainty and compares relevant mitigation and transmission scenarios. An appropriate threshold will depend on the location, number of ICU beds available for COVID-19, available mitigation options, feasible mitigation strengths, and tolerated durations of intensified mitigation.
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Affiliation(s)
- Manuela Runge
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, United States of America
| | - Reese A. K. Richardson
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, United States of America
| | - Patrick A. Clay
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, United States of America
| | - Arielle Bell
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, United States of America
| | - Tobias M. Holden
- Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Manisha Singam
- Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Natsumi Tsuboyama
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, IL, United States of America
| | - Philip Arevalo
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, United States of America
| | - Jane Fornoff
- Illinois Department of Public Health, Springfield, IL, United States of America
| | - Sarah Patrick
- Illinois Department of Public Health, Springfield, IL, United States of America
| | - Ngozi O. Ezike
- Illinois Department of Public Health, Springfield, IL, United States of America
| | - Jaline Gerardin
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, United States of America
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Holden TM, Simon MA, Arnold DT, Halloway V, Gerardin J. Structural racism and COVID-19 response: higher risk of exposure drives disparate COVID-19 deaths among Black and Hispanic/Latinx residents of Illinois, USA. BMC Public Health 2022; 22:312. [PMID: 35168585 PMCID: PMC8845334 DOI: 10.1186/s12889-022-12698-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 02/02/2022] [Indexed: 01/15/2023] Open
Abstract
Background Structural racism has driven and continues to drive policies that create the social, economic, and community factors resulting in residential segregation, lack of access to adequate healthcare, and lack of employment opportunities that would allow economic mobility. This results in overall poorer population health for minoritized people. In 2020, Black and Hispanic/Latinx communities throughout the United States, including the state of Illinois, experienced disproportionately high rates of COVID-19 cases and deaths. Public health officials in Illinois implemented targeted programs at state and local levels to increase intervention access and reduce disparities. Methods To quantify how disparities in COVID outcomes evolved through the epidemic, data on SARS-CoV-2 diagnostic tests, COVID-19 cases, and COVID-19 deaths were obtained from the Illinois National Electronic Disease Surveillance System for the period from March 1 to December 31, 2020. Relative risks of COVID-19 cases and deaths were calculated for Black and Hispanic/Latinx vs. White residents, stratified by age group and epidemic interval. Deaths attributable to racial/ethnic disparities in incidence and case fatality were estimated with counterfactual simulations. Results Disparities in case and death rates became less drastic after May 2020, but did not disappear, and were more pronounced at younger ages. From March to May of 2020, the risk of a COVID-19 case for Black and Hispanic/Latinx populations was more than twice that of Whites across all age groups. The relative risk of COVID-19 death reached above 10 for Black and Hispanic/Latinx individuals under 50 years of age compared to age-matched Whites in the early epidemic. In all Illinois counties, relative risk of a COVID-19 case was the same or significantly increased for minoritized populations compared to the White population. 79.3 and 86.7% of disparities in deaths among Black and Hispanic/Latinx populations, respectively, were attributable to differences in age-adjusted incidence compared to White populations rather than differences in case fatality ratios. Conclusions Racial and ethnic disparities in the COVID-19 pandemic are products of society, not biology. Considering age and geography in addition to race/ethnicity can help to identify the structural factors driving poorer outcomes for certain groups. Studies and policies aimed at reducing inequalities in disease exposure may reduce disparities in mortality more than those focused on drivers of case fatality. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-022-12698-9.
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Affiliation(s)
- Tobias M Holden
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Melissa A Simon
- Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, USA
| | - Damon T Arnold
- Blue Cross Blue Shield of Illinois, Chicago, IL, USA.,Illinois Department of Public Health, Springfield, IL, USA
| | | | - Jaline Gerardin
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA.
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Holden TM, Richardson RAK, Arevalo P, Duffus WA, Runge M, Whitney E, Wise L, Ezike NO, Patrick S, Cobey S, Gerardin J. Geographic and demographic heterogeneity of SARS-CoV-2 diagnostic testing in Illinois, USA, March to December 2020. BMC Public Health 2021; 21:1105. [PMID: 34107947 PMCID: PMC8189821 DOI: 10.1186/s12889-021-11177-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/26/2021] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Availability of SARS-CoV-2 testing in the United States (U.S.) has fluctuated through the course of the COVID-19 pandemic, including in the U.S. state of Illinois. Despite substantial ramp-up in test volume, access to SARS-CoV-2 testing remains limited, heterogeneous, and insufficient to control spread. METHODS We compared SARS-CoV-2 testing rates across geographic regions, over time, and by demographic characteristics (i.e., age and racial/ethnic groups) in Illinois during March through December 2020. We compared age-matched case fatality ratios and infection fatality ratios through time to estimate the fraction of SARS-CoV-2 infections that have been detected through diagnostic testing. RESULTS By the end of 2020, initial geographic differences in testing rates had closed substantially. Case fatality ratios were higher in non-Hispanic Black and Hispanic/Latino populations in Illinois relative to non-Hispanic White populations, suggesting that tests were insufficient to accurately capture the true burden of COVID-19 disease in the minority populations during the initial epidemic wave. While testing disparities decreased during 2020, Hispanic/Latino populations consistently remained the least tested at 1.87 tests per 1000 population per day compared with 2.58 and 2.87 for non-Hispanic Black and non-Hispanic White populations, respectively, at the end of 2020. Despite a large expansion in testing since the beginning of the first wave of the epidemic, we estimated that over half (50-80%) of all SARS-CoV-2 infections were not detected by diagnostic testing and continued to evade surveillance. CONCLUSIONS Systematic methods for identifying relatively under-tested geographic regions and demographic groups may enable policymakers to regularly monitor and evaluate the shifting landscape of diagnostic testing, allowing officials to prioritize allocation of testing resources to reduce disparities in COVID-19 burden and eventually reduce SARS-CoV-2 transmission.
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Affiliation(s)
- Tobias M Holden
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Reese A K Richardson
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
| | - Philip Arevalo
- Department of Ecology and Evolutionary Biology, University of Chicago, Chicago, IL, USA
| | - Wayne A Duffus
- Center for Preparedness and Response, Division of State and Local Readiness, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Illinois Department of Public Health, Springfield, IL, USA
| | - Manuela Runge
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA
| | - Elena Whitney
- Department of Ecology and Evolutionary Biology, University of Chicago, Chicago, IL, USA
| | - Leslie Wise
- Illinois Department of Public Health, Springfield, IL, USA
| | - Ngozi O Ezike
- Illinois Department of Public Health, Springfield, IL, USA
| | - Sarah Patrick
- Illinois Department of Public Health, Springfield, IL, USA
| | - Sarah Cobey
- Department of Ecology and Evolutionary Biology, University of Chicago, Chicago, IL, USA
| | - Jaline Gerardin
- Department of Preventive Medicine and Institute for Global Health, Northwestern University, Chicago, IL, USA.
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Holden TM, Richardson RA, Arevalo P, Duffus WA, Runge M, Whitney E, Wise L, Ezike NO, Patrick S, Cobey S, Gerardin J. Geographic and demographic heterogeneity of SARS-CoV-2 diagnostic testing in Illinois, USA, March to December 2020. medRxiv 2021:2021.04.14.21255476. [PMID: 33907762 PMCID: PMC8077585 DOI: 10.1101/2021.04.14.21255476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background Availability of SARS-CoV-2 testing in the United States (U.S.) has fluctuated through the course of the COVID-19 pandemic, including in the U.S. state of Illinois. Despite substantial ramp-up in test volume, access to SARS-CoV-2 testing remains limited, heterogeneous, and insufficient to control spread. Methods We compared SARS-CoV-2 testing rates across geographic regions, over time, and by demographic characteristics (i.e., age and racial/ethnic groups) in Illinois during March through December 2020. We compared age-matched case fatality ratios and infection fatality ratios through time to estimate the fraction of SARS-CoV-2 infections that have been detected through diagnostic testing. Results By the end of 2020, initial geographic differences in testing rates had closed substantially. Case fatality ratios were higher in non-Hispanic Black and Hispanic/Latino populations in Illinois relative to non-Hispanic White populations, suggesting that tests were insufficient to accurately capture the true burden of COVID-19 disease in the minority populations during the initial epidemic wave. While testing disparities decreased during 2020, Hispanic/Latino populations consistently remained the least tested at 1.87 tests per 1000 population per day compared with 2.58 and 2.87 for non-Hispanic Black and non-Hispanic White populations, respectively, at the end of 2020. Despite a large expansion in testing since the beginning of the first wave of the epidemic, we estimated that over half (50-80%) of all SARS-CoV-2 infections were not detected by diagnostic testing and continued to evade surveillance. Conclusions Systematic methods for identifying relatively under-tested geographic regions and demographic groups may enable policymakers to regularly monitor and evaluate the shifting landscape of diagnostic testing, allowing officials to prioritize allocation of testing resources to reduce disparities in COVID-19 burden and eventually reduce SARS-CoV-2 transmission.
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Affiliation(s)
- Tobias M Holden
- Northwestern University Feinberg School of Medicine,
Chicago IL
| | - Reese A.K. Richardson
- Department of Chemical and Biological Engineering,
Northwestern University, Evanston IL
| | - Philip Arevalo
- Department of Ecology and Evolutionary Biology, University
of Chicago, Chicago IL
| | - Wayne A. Duffus
- Center for Preparedness and Response, Division of State and
Local Readiness, Centers for Disease Control and Prevention, Atlanta GA
- Illinois Department of Public Health, Springfield IL
| | - Manuela Runge
- Department of Preventive Medicine and Institute for Global
Health, Northwestern University, Chicago IL
| | - Elena Whitney
- Department of Ecology and Evolutionary Biology, University
of Chicago, Chicago IL
| | - Leslie Wise
- Illinois Department of Public Health, Springfield IL
| | | | - Sarah Patrick
- Illinois Department of Public Health, Springfield IL
| | - Sarah Cobey
- Department of Ecology and Evolutionary Biology, University
of Chicago, Chicago IL
| | - Jaline Gerardin
- Department of Preventive Medicine and Institute for Global
Health, Northwestern University, Chicago IL
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Coombs GJ, Cowley RA, Buyers WJL, Svensson EC, Holden TM, Jones DA. Magnetic excitations in antiferromagnetic Mn1-cZncF2at large Zn concentrations. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/9/11/022] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tindall DA, Steinitz MO, Holden TM. Observation of the stabilization of a second lock-in phase in holmium at 42 K with a wave vector of 0.2 reciprocal-lattice units. Phys Rev B Condens Matter 1993; 47:5463-5464. [PMID: 10006720 DOI: 10.1103/physrevb.47.5463] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Jackman JA, Holden TM, Buyers WJ, Vogt O, Genossar J. Systematic study of the lattice dynamics of the uranium rocksalt-structure compounds. Phys Rev B Condens Matter 1986; 33:7144-7153. [PMID: 9938044 DOI: 10.1103/physrevb.33.7144] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bartlett MW, Egelstaff PA, Holden TM, Stinson RH, Sweeny PR. Structural changes in tendon collagen resulting from muscular dystrophy. Biochim Biophys Acta 1973; 328:213-20. [PMID: 4761989 DOI: 10.1016/0005-2795(73)90347-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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