WASHINGTON — To more accurately quantify disaster-related deaths, injuries, and illnesses, the Federal Emergency Management Agency and other agencies supporting disaster response should adopt a uniform national framework of data collection approaches and methods for distinguishing direct from indirect disaster deaths, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine. A Framework for Assessing Mortality and Significant Morbidity After Large-Scale Disasters also examines the methods used to record and report COVID-19 cases and deaths.

In all disasters, disaster-related mortality and morbidity estimates can evolve. Hurricanes and wildfires can occur over days or weeks, and some death recording systems have lags, especially if they are paper-based. Disasters like Hurricane Maria, and more recently, the COVID-19 pandemic, have demonstrated how multiple methods for assessing mortality and morbidity can create confusion or the impression that data are being manipulated.

All Stafford Act declarations — which enable emergency spending — should require disaster-impacted states and regions to comply with the reporting requirements of individual counts and population estimates described in the report. It recommends that state, local, tribal, and territorial (SLTT) entities produce and use both individual counts and population estimates of deaths, illnesses, and injuries to more completely describe the impact of disasters. Individual counts are based on counts of individual incidences recorded in administrative systems (such as data from death records or case investigations), while population estimates are based on statistical approaches (such as estimation of “excess” death relative to a historic baseline or surveys of population samples). Both approaches for estimating mortality and morbidity following disasters have unique analytical strengths and uses, and they should be used in tandem to develop the fullest picture of disaster impacts.

SLTT entities should also establish standards for which mortality and morbidity data should be consistently tracked across common types of disasters, such as hurricanes and wildfires, as well as which data should be uniformly tracked across all disasters, the report recommends. Additionally, the incorporation of data on social determinants of health in morbidity and mortality assessments (including race, housing, and ZIP code) could be used to identify groups most at risk and help target public health efforts more successfully.

Data on disaster-related mortality and morbidity have critical implications beyond response, recovery, and preparedness efforts. These data are used to limit further public health consequences; detect and track epidemiological trends; shape public messaging; and determine needs for resources such as food, water, shelter, and mental health services.

“Although disasters are growing in number and severity, there hasn’t been a standardized approach to answering the question, ‘How many deaths and severe morbidities were caused by this event?’” said Ellen MacKenzie, dean of the Johns Hopkins Bloomberg School of Public Health and chair of the committee that wrote the report. “Mortality and morbidity data present a significant opportunity to inform response, recovery, mitigation, and preparedness efforts. The committee strove to produce recommendations that facilitate access to actionable data, and help the disaster management enterprise to meet their core mission of protecting communities — especially the most vulnerable.”

Alongside the uniform framework for estimating disaster-related mortality and morbidity, the report also provides consistent case definitions for direct, indirect, and partially attributable disaster deaths. It defines direct deaths as those that are attributable to the physical forces of a disaster, such as drowning, injury from flying debris, or radiation exposure. Indirect deaths are due to unsafe or unhealthy conditions in the aftermath — for example, lack of access to essential medications or treatments (such as dialysis or insulin), or carbon monoxide poisoning from a poorly placed generator. The term partially attributable encompasses those deaths that would be unlikely to have occurred “but for” the disaster, but cannot be tied definitively to it.

Medical examiners, coroners, and other medical certifiers should receive guidance and training on the proper certification of individual deaths (direct, indirect, or partially attributable). The report recommends that the Centers for Disease Control and Prevention (CDC) fund and re-launch the Medical Examiner and Coroner Information Sharing Program, which would facilitate communication among the medicolegal death investigation professionals, the public health community, and federal agencies.  In addition, CDC’s National Center for Health Statistics should fund and support the transition of the remaining states and territories with paper-based death registration systems to electronic death registration systems.

The report also recommended ways to address the uncertainties that have arisen in COVID-19 case and death counts — both of which have likely been underestimated. Whether an individual with respiratory illness is included in the COVID-19 case count often depends on whether a test was available and reported, while deaths from COVID-19 can be either over- or under-attributed to COVID-19 on death certificates.

An appendix to the report, drafted by two committee members, addresses recent controversies in the assessment of COVID-19-related mortality and morbidity. The authors of the appendix suggest that, to avoid confusion, statistics derived from COVID-19 case counts should be referred to as “reported infections” and “reported deaths” from COVID-19, rather than as “total infections” or the “death toll.” Suspected and probable cases should also be reported separately from confirmed cases. Meanwhile, the total mortality (“death toll”) from COVID-19 should be reported using population estimation approaches similar to methods CDC uses for tracking deaths from pneumonia or seasonal influenza. When feasible, population estimation methods are also preferable for guiding policy decisions, such as re-opening strategies and targeting aid to hardest-hit areas and populations. Finally, the CDC should recommend common processes for reporting cases and deaths and metrics, to help ensure that comparisons among states and other population groups are more meaningful.

The study — carried out by the Committee on Best Practices in Assessing Mortality and Significant Morbidity Following Large-Scale Disasters — was sponsored by the Federal Emergency Management Agency. The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.

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