A Framework for Assessing Mortality and Morbidity After Large-Scale Disasters (2020) / Chapter Skim
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Appendix C: Assessing Morbidity and Mortality Associated with the COVID-19 Pandemic: A Case Study Illustrating the Need for the Recommendations in This Report
Appendix C: Assessing Morbidity and Mortality Associated with the COVID-19 Pandemic: A Case Study Illustrating the Need for the Recommendations in This Report
Pages 201-226
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From page 201... ...
The coronavirus disease 2019 (COVID-19) pandemic has generated a sea of numbers: cumulative totals and daily numbers of new cases, individuals hospitalized and recovered, deaths and death rates, numbers tested, testing capacity, and undiagnosed and asymptomatic cases.
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From page 202... ...
Meanwhile, the population estimation approach typically takes more time, and suffers from the additional weakness of not being useful for determining which specific individuals might have been affected and which would have died or become ill even in the absence of the disaster. However, population estimation methods provide a much more complete picture of the entire population affected by the disaster and are preferred (when available)
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From page 203... ...
Population-Based Estimates Sero-prevalence • Estimate total • Require testing • Identify trends in surveys number of infected scientifically infection rates individuals, selected • Assess impact of including those representative social distancing without symptoms samples of the and other public or not tested population, health efforts • Identify trends and including many • Assess levels of differences across who are not immunity in the sociodemographic symptomatic population groups Excess • Rely on existing • Require complex • In-depth analysis morbidity data systems (vital statistical modeling after the pandemic and mortality statistics, electronic and assumptions, estimates medical records, which take time etc.)
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From page 204... ...
And some cases are even more challenging, such as the person who survived a wildfire but then returned to his burned-out home and committed suicide.3 With regard to reporting, as in normal times, deaths during disasters are reported to state health departments through vital registration systems, which can take days or even weeks. For this reason, deaths and injuries in disasters are also often reported to and rapidly tabulated by public health emergency operations centers.
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From page 205... ...
These definitions can evolve as more is learned, and they often include options for naming someone as a "probable," "presumptive," or "confirmed" case, which can be critical for carrying out effective contact tracing. Importantly, contact tracing is a primary purpose of public health surveillance: clinicians are required to report cases to local or state health departments, which use this information to trace case contacts and help stem the outbreak.
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From page 206... ...
While physicians have a responsibility to report COVID cases, and health departments publish guidance about what should be reported and how, the changing nature of this guidance has made it difficult for busy practitioners to know what to do. To mitigate the risk of physician under-reporting, laboratories are also required to report positive test results, so that health departments can reach out to their physicians to gather additional data.
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From page 207... ...
As testing capacity grew in April, May, and June, so did the number of positive results, possibly "catching up" with actual cases and perhaps not reflecting a true rising incidence of new infections. Similarly, reducing the amount of testing would be expected to reduce the reported case count, which led public health officials to adjust recommendations for reopening according to testing numbers.
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From page 208... ...
Because COVID-19 cases are likely to be undercounted by public health, so are COVID-19 associated deaths based on case counts.17 An alternative source of individual-level mortality data is vital statistics, which uses different definitions and processes than public health case counting and is essentially complete (i.e., nearly every person who dies in the United States is accounted for on a death certificate)
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From page 209... ...
For instance, there have been claims offered without evidence that doctors are being "coached" to mark COVID-19 as the cause of death on death certificates even when it is not, to inflate the pandemic's death toll for political purposes.21 In response, some states elected to not include deaths without a mention of COVID-19 on the death certificate in their official counts, even if the person had tested positive and was included in the public health surveillance database. In Colorado, this corresponded to a 24 percent reduction in deaths from COVID-19, as only 878 of 1,150 deaths (as of May 15, 2020)
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From page 210... ...
Second, recent case fatality rates have probably also been lower because the medical care provided to infected individuals has improved, though as hospitals in the South and West become as overwhelmed with cases as those in the New York City area were in April and May, that effect too may diminish.27,28 As with case counts, differences in the way COVID-19 deaths are recorded and tabulated described in this section create challenges for monitoring the pandemic. Standardizing mortality data and reporting (Recommendation 3-2)
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From page 211... ...
presented as precise numbers down to the single case -- and even though individual counting methods are critical when it comes to certain tasks such as contact tracing and assigning death benefits to individuals -- these statistics are in fact estimates of the true total mortality or morbidity. To illustrate this, consider that even the two primary sources of data for individual counts of deaths -- public health case counts and vital statistics -- can be expected to generate different totals.29 The COVID-19 pandemic further demonstrates that when case counts are the product of evolving case definitions, testing procedures, and reporting processes, the estimates generated through case counting can change (and hopefully improve)
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From page 212... ...
Experiences to date with using statistical estimation methods to assess COVID-19 morbidity and mortality have shown smaller, but still very significant estimation differences between case counting and statistical estimation methods, as summarized below. Using Survey Sampling Methods to Assess Total COVID-19 Morbidity and Mortality Efforts are under way to use survey methods to assess total morbidity and mortality of COVID-19.
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From page 213... ...
For example, "sentinel testing" on samples of individuals at high risk of infection, such as health care workers or contacts of known cases,39 have helped improve understanding of viral transmission risk and risk factors for more severe disease.40 COVID-19 has demonstrated the value of ongoing surveillance efforts, such as the Centers for Disease Control and Prevention's (CDC's) Outpatient Influenza-like Illness Surveillance Network (ILINet)
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From page 214... ...
2020. COVIDView -- A weekly surveillance summary of U.S.
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From page 215... ...
Also, the National Syndromic Surveillance Program (NSSP) , which tracks emergency department visits in 47 states, has been extended to include COVID-19-like illness (fever and cough or shortness of breath or difficulty breathing)
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For instance, excess mortality is the standard way to determine the overall death toll for influenza each year. Because pneumonia is often 44 Havers, F
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From page 217... ...
NOTES: Data during recent weeks are incomplete because of the lag in time between when the death occurred and when the death certificate is completed, submitted to NCHS and processed for reporting purposes. MMRW = Morbidity and Mortality Weekly Report; PIC = Pneumonia, Influenza, or COVID.
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From page 218... ...
For instance, The Economist found sharp increases in cardiac arrest 911 calls and deaths as well as confirmed COVID-19 deaths in March and early April 2020 in New York City (see Figure C-3) .51 Similarly, based on data compiled by NCHS, The New York Times estimated that there had been 23,000 excess deaths in New York City between March 15 and May 2, 2020, leading to a total number of deaths that was more than three times the normal amount.52 A more comprehensive analysis published by The New York Times estimated that by May 13, more than 100,000 Americans had already died as a result of the pandemic, rather than the 83,000 whose deaths had been directly attributed to the disease by that date.53 The Economist maintains a comparison of excess deaths across countries.54 In May 2020 the New York City Department of Health and Mental Hygiene published a preliminary estimate of excess mortality in New York City from March 11 through May 2.
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From page 219... ...
2020. Deaths from cardiac arrests have surged in New York City.
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From page 220... ...
† Death in a person without a positive test for SARS-CoV-2 RNA but for whom COVID-19, SARS-CoV-2, or a related term was listed as an immediate, underlying, or contributing cause of death on the death certificate. § Total excess all-cause deaths were calculated as observed deaths minus expected deaths as determined by a seasonal regression model using mortality data from the period January 1, 2015–May 2, 2020.
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From page 221... ...
They estimated that there were 122,300 more deaths than would typically be expected at that time of year, 28 percent higher than the official tally of COVID-19-reported deaths during that period based on case counts. The patterns varied substantially across geographical areas; Figure C-5 illustrates the results from New York City and State, the hardest hit areas during this period.57 The COVID-19 pandemic can be used to demonstrate that many of the deaths missed by case counting but captured using excess mortality methods are indirect deaths.
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From page 222... ...
, deaths recorded as due to COVID-19; orange (narrow middle section) , additional pneumonia and influenza excess deaths not coded as due to COVID-19; and beige (top)
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From page 223... ...
Whether these excess deaths should be regarded as "caused by" the pandemic is a matter of definitional dispute, and an illustration of how population estimation methods require judgments to interpret as well as judgments to carry out. The methods research described under Recommendation 4-1 would address these issues and help to ensure the validity and utility of excess mortality estimates in future disasters.
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From page 224... ...
So, use of population estimation methods such as serological surveys to assess infection rates will predictably generate higher estimates than case counting methods, while using individual case counts to assess mortality will predictably generate low estimates. Doing so in combination will therefore suggest large numbers of non-fatal infection (i.e., generating an artificially low case fatality rate)
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From page 225... ...
Total mortality, or the "death toll" from COVID-19, should only be reported using population estimation approaches, preferably using the same methods as are used for seasonal influenza. These methods produce a more complete picture of the consequences of the pandemic and are preferable for guiding policy decisions, such as about reopening strategies and targeting aid to areas and populations most affected.
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