The University of Tennessee, Knoxville.

Understanding COVID-19 Death Reporting and Statistics

A Policy Brief by the Howard H. Baker Jr. Center for Public Policy in Partnership with the Coronavirus-19 Outbreak Response Experts (CORE-19)

August 16, 2020
Tennessee State Capitol and Flag
Using publicly available data from emerging research on COVID-19, this brief was written and reviewed by the Coronavirus-19 Outbreak Response Experts (CORE-19) at the University of Tennessee, Knoxville. The brief explains death reporting and statistics as it relates to the COVID-19 pandemic.

Understanding COVID-19 Death Reporting and Statistics

There are many concerns circulating in the news and on social media regarding the COVID-19 death statistics being reported by the CDC and other organizations. Some are concerned that the deaths are being over-counted, while others are concerned about under-reporting. This brief aims to provide context on how death reporting is done in the United States, in general and specific to COVID-19.

Key Points

  • Death certificates are legal documents with standardized reporting processes that include multiple levels of checks for accuracy and completeness; COVID-19 death reporting follows these same processes.
  • Death certificates are completed by different individuals, depending on the state or jurisdiction or manner of death, with varying levels of medical training; as such, death certificates are not without errors.
  • National COVID-19 mortality statistics reported by the CDC are considered provisional because completing the certificate takes time, states have different processes and report at different rates, and COVID-19 deaths take additional time because they must be coded by a person.
  • Of all reported COVID-related deaths in the United States, 94% of these have COVID-19 listed as the underlying cause of death.
  • Accurate reporting of COVID-19 deaths will become more challenging during the upcoming influenza season due to similar clinical signs and possible co-infections with the two viruses.

Death Certificate Cause-of-Death Coding

Cause of death, as reported on death certificates, is one of the most important methods of mortality surveillance. Every death in the United States has a corresponding death certificate, which provides critical information about the circumstances and causes of death. A cause of death statement is a clinical judgment or a medical opinion made typically by a physician, coroner, or medical examiner. However, this varies from state to state, and even within a state, and can include certifiers with varying degrees of medical training. The Cause of Death section on a death certificate is coded in a very specific manner, and it is important to distinguish what information is documented in Part I and Part II of this section of the death certificate. 

Important Definitions on Cause of Death

Part I describes the chain of events that directly caused the death. 
  • Immediate Cause: final disease, injury, or complication directly causing death
  • Intermediate Cause(s): conditions that typically have multiple possible underlying etiologies or that occur between the underlying and immediate causes of death
  • Underlying Cause: disease or injury that initiated the events resulting in death
Part II describes other significant conditions contributing to death but not resulting in the underlying cause given in Part I. (e.g., pre-existing or comorbid conditions)
Part I describes the chain of events that led to death. The immediate cause of death is listed on line a, and the condition(s) that preceded the immediate cause of death are listed below in a logical sequence on lines b, c, and d. (See Figure 1.) These lines indicate intermediate cause(s) and underlying cause of death. The underlying cause of death is always listed on the lowest used line of Part I. The approximate intervals of each line item, from time of onset to death, is listed to the right of each line.
Part II describes any other comorbidities that contributed to death but that do not result in the sequence of events that led to death as listed in Part I. Not all conditions present at the time of death need to be reported in Part II. Only conditions that contribute to death should be reported.
Sample Death Certificate
Figure 1. Example of a properly completed cause-of-death section of the death certificate. 
Another example for Part I of a death certificate for a motor vehicle accident might list the motor vehicle accident as the underlying cause of death (line d), leading to blunt force trauma of abdomen (line c), leading to contusion of spleen (line b), with the immediate cause of death being listed as splenic rupture with intra-abdominal hemorrhage (line a).
Leading cause of death statistics reported in the United States are based on the underlying cause of death. Multiple cause of death certificates are based on the single underlying cause and up to 20 additional multiple causes of death included in Part 1 of the death certificate.
Administration
Legal authority for the registration of all vital statistics lies with each state individually, and vital event reporting is mandatory in the United States. Because birth and death certificates are needed for a variety of legal reasons, these statistics are virtually complete, i.e., births and deaths are not under-reported in the United States. Vital records are considered legal documents. As such, accuracy and completeness before registration is of extreme importance, as amendments or changes after filing require proof of accuracy.
Once complete, the death certificate is certified by the authority (e.g., physician, medical examiner, coroner) who determined the cause of death. Death certificates are then provided to the local vital records office for registration and filing. Local offices then submit their data to the state vital statistics office, which in turn reports to the federal government. National statistics, therefore, rely on a cooperative relationship between states, territories, and the federal government.
There are checks for completion and accuracy at each level. However, death certificates are not without error. Depending on the source and type of death, errors can occur on 33-41% of certificates with regards to cause of death reporting. Cardiovascular diseases are known to be over-reported on death certificates. Death certificates are thought to be more accurate with regards to cancer as underlying cause of death.

COVID-19 and Cause-of-Death Coding

These rules for properly completing the cause of death section of a death certificate remain constant during the COVID-19 pandemic. Reporting of COVID-19 deaths takes time, so current national mortality statistics are considered provisional. All death certificates take time to complete and file at the local level. Different states and jurisdictions have different processes for reporting deaths to the National Center for Health Statistics (NCHS). Finally, COVID-19 death reporting takes additional time, as these are not coded automatically by NCHS, but require coding by a person due to the novelty of this virus.
If COVID-19 contributed to a death, then it should be listed on the lowest used line in Part I, indicating that is the underlying cause of death. (See Figure 2.) Testing for COVID-19 should always be performed when possible, but when a definitive diagnosis cannot be made and the disease is suspected, it is acceptable to report COVID-19 on the death certificate as “probable.” (See Figure 3.) People who have COVID-19 at the time of death, but whose death was due to some other event (e.g., motor vehicle accident), will have COVID-19 listed in Part 2 of the death certificate. According to the World Health Organization, these deaths should not be counted as a COVID-19 death.
94% of reported COVID-19 deaths have COVID-19 listed as the underlying cause of death.
Currently, 94% of reported COVID-19 deaths have COVID-19 listed as the underlying cause of death. However, reported COVID-19 deaths include all those that list COVID-19 under any section of Part I. In other words, reported COVID-19 deaths may have COVID-19 listed as the underlying cause of death (as is the case in 94% of all COVID-related deaths), intermediate cause of death, or immediate cause of death. Currently, the accuracy of COVID-19 death certificates and reporting is unknown, as data are provisional.
The CDC publishes different COVID-related provisional death statistics on a regular basis, which are available, here
. Example of properly completed cause-of-death section of the death certificate, where COVID-19 was an underlying cause of death
Figure 2: Example of properly completed cause-of-death section of the death certificate, where COVID-19 was an underlying cause of death.
Example of properly completed cause-of-death section of the death certificate, where COVID-19 was a probable underlying cause of death
Figure 3: Example of properly completed cause-of-death section of the death certificate, where COVID-19 was a probable underlying cause of death

COVID-19 Official Case Definition

The clinical criteria for COVID-19 include the following:
At least two of the following symptoms: fever (measured or subjective), chills, rigors, myalgia, headache, sore throat, new olfactory and taste disorder(s). OR 
At least one of the following symptoms: cough, shortness of breath, or difficulty breathing. OR
Severe respiratory illness with at least one of the following:
Clinical or radiographic evidence of pneumonia, OR
Acute respiratory distress syndrome (ARDS).
AND
No alternative more likely diagnosis.”
The laboratory criteria for COVID-19 include the following:
“Laboratory evidence using a method approved or authorized by the U.S. Food and Drug Administration (FDA) or designated authority:
Confirmed laboratory evidence:
  • Detection of severe acute respiratory syndrome coronavirus 2 ribonucleic acid (SARS-CoV-2 RNA) in a clinical specimen using a molecular amplification detection test.
Presumptive laboratory evidence:
  • Detection of specific antigen in a clinical specimen
  • Detection of specific antibody in serum, plasma, or whole blood indicative of a new or recent infection*
*Serologic methods for diagnosis are currently being defined.”
The probable case criteria for COVID-19 include the following:
“Meets clinical criteria AND epidemiologic evidence with no confirmatory laboratory testing performed for COVID-19.
Meets presumptive laboratory evidence AND either clinical criteria OR epidemiologic evidence.
Meets vital records criteria with no confirmatory laboratory testing performed for COVID-19.”

Influenza Death Reporting vs. COVID-19 Death Reporting

The CDC defines seasonal influenza-related deaths as, “deaths that occur in people for whom influenza infection was likely a contributor to the cause of death, but not necessarily the primary cause of death.” Deaths from influenza are likely underreported for several reasons. The CDC acknowledges, “influenza is infrequently listed on death certificates of people who die from flu-related complications,” and “many flu-related deaths occur one or two weeks after a person’s initial infection, either because the person may develop a secondary bacterial co-infection (such as bacterial pneumonia) or because influenza can aggravate an existing chronic illness."
Furthermore, the CDC does not base its seasonal influenza mortality estimates solely on death certificates that specifically list influenza. Instead, the CDC’s seasonal influenza mortality estimates are based on statistical and mathematical modeling. The CDC’s model “uses a ratio of deaths-to-hospitalizations in order to estimate the total influenza-associated deaths from the estimated number of influenza-associated hospitalizations.” This modeling is needed because influenza can give rise to other complications – like pneumonia, congestive heart failure, COPD, etc. – that may lead to death, and influenza may not be identified in many of these instances. The CDC states, “Only counting deaths where influenza was included on a death certificate would be a gross underestimation of seasonal influenza’s true impact.”
COVID-19 deaths are likely underreported.
Similarly, COVID-19 deaths are likely underreported. Like influenza, COVID-19 has led to a large volume of deaths that must be quickly processed and counted, there is a lack of sufficient testing nationwide, and there may be different coding of COVID-19 deaths if secondary complications arise. Although COVID-19 is a reportable disease in all 50 states and influenza is not a reportable disease in adults, these factors still strongly suggest that national COVID-19 deaths are underreported. Furthermore, the sheer number of COVID-19 deaths has far outstripped the deaths associated with a typical influenza season, making accurate COVID-19 death reporting more difficult.
While the medical guidelines for completing the cause of death section of the death certificate remain unchanged in the face of COVID-19, some people want to artificially lower COVID-19 death reporting by only counting lab-confirmed cases in their death tallies and excluding “probable COVID-19” cases. This strategy has been supported by some government officials. As previously mentioned, the CDC strongly discourages this strategy when estimating seasonal influenza mortality, since this is known to generate “a gross underestimation” of influenza’s impact. When these factors are considered together, the net result is an underreporting of national COVID-19 deaths.
Unfortunately, accurately reporting COVID-19 deaths is expected to become even more challenging this fall and winter, when both COVID-19 and influenza are circulating simultaneously. These two respiratory pathogens have very similar clinical signs and will be difficult – if not impossible – to distinguish without widely available testing for both viruses. Additionally, co-infection with COVID-19 and influenza may further complicate reporting.
Send any additional questions to the CORE-19 team. 
core19@utk.edu | 865-321-1299

Coronavirus-19 Outbreak Response Experts (CORE-19) 

Policy Brief Authors
Elizabeth Molinet

Elizabeth Molinet, DVM & MPH Candidate

Molinet is a dual DVM-MPH student at the University of Tennessee College of Veterinary Medicine and Department of Public Health. Her interests are in zoonotic diseases and the One Health Initiative, and she hopes to work at the CDC upon graduation. She is currently a COVID-19 case and contact tracer at the East Tennessee Regional Health Office.
Dr. Kristina Kintziger

Dr. Kristina W. Kintziger, PhD, MPH

Kintziger is an Assistant Professor in the Department of Public Health and the co-Director of the Doctoral Program. She has worked in academia and public health practice. Prior to coming to Tennessee, she served as an epidemiologist and biostatistician at the Florida Department of Health. She is an environmental and infectious disease epidemiologist. Kintziger is a member of the CORE-19 Steering Committee
Coronavirus Outbreak Response Experts (CORE-19)
Steering Committee
Dr. Kathleen Brown

Dr. Kathleen C. Brown, PhD, MPH

Brown is an Associate Professor of Practice in the Department of Public Health and the Program Director for the Master's in Public Health (MPH) degree. Her research focuses on the health and well-being of individuals and communities. She has experience in local public health in epidemiology, risk reduction and health promotion.
Dr. Katie Cahill

Dr. Katie A. Cahill, PhD

Cahill is the Associate Director of the Howard H. Baker Jr. Center for Public Policy. She also is the Director of the Center's Leadership & Governance program and holds a courtesy faculty position in the Department of Political Science. Her area of expertise is public health policy. She leads the Healthy Appalachia project. 
Dr. Matthew Murray

Dr. Matthew N. Murray, PhD

Murray is the Director of the Howard H. Baker Jr. Center for Public Policy. He also is the Associate Director of the Boyd Center for Business and Economic Research and is a professor in the Department of Economics in the Haslam College of Business. He has led the team producing Tennessee's annual economic report to the governor since 1995. 
Dr. Agricola Odoi

Dr. Agricola Odoi, BVM, MSc, PhD

Odoi is a professor of epidemiology at the University of Tennessee College of Veterinary Medicine. He teaches quantitative and geographical epidemiology and his research interests are in population health and impact of place on health and access to health services. He was a public health epidemiologist before joining academia. Odoi is a member of the CORE-19 Steering Committee. 
Dr. Marcy Souza

Dr. Marcy J. Souza, DVM, MPH

Souza is an associate professor and Director of Veterinary Public Health in the UT College of Veterinary Medicine.  Her teaching and research focuses on zoonotic diseases and food safety issues. 
Disclaimer: the information in this policy brief was produced by researchers, not medical or public health professionals, and is based on their best assessment of the existing knowledge and data available on the topic. It does not constitute medical advice and is subject to change as additional information becomes available. The information contained in this brief is for informational purposes only. No material in this brief is intended to be a substitute for professional medical advice, diagnosis or treatment, and the University of Tennessee makes no warranties, expressed or implied, regarding errors or omissions and assumes no legal liability or responsibility whatsoever for loss or damage resulting from the use of information provided.
Howard H. Baker Jr Center for Public Policy
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Email: bakercenter@utk.edu
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