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How Accurate Is the Coronavirus Death Toll?

— A forensic pathologist's perspective

Last Updated May 12, 2020
MedpageToday
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At an , Deborah Birx, MD, the response coordinator for the White House coronavirus task force, said, "There are other countries that if you had a pre-existing condition and let's say the virus caused you to go to the ICU and then have a heart or kidney problem -- some countries are recording that as a heart issue or a kidney issue and not a COVID-19 death. Right now ... if someone dies with COVID-19 we are counting that as a COVID-19 death."

That statement might make you conclude that the U.S. COVID-19 data will be skewed to count many people who died with COVID-19 as an irrelevant background condition, inflating the numbers up from the count of those who clearly died from the effects of the virus. Yet the , the , and many other news agencies have reported stories showing that the tally of COVID-19 deaths in the United States and elsewhere in the world is almost certainly an undercount. They cite epidemiological data showing that the overall numbers of deaths during the months of this pandemic have far outpaced the death rate during the same period in recent past years, and postulate that the lack of available testing might be a reason why COVID-19 would not make it onto a death certificate.

So which one is it? Are we undercounting or overcounting? Can we trust the numbers?

It's complicated. In the United States, most death investigation systems are funded and organized on a county basis across hundreds of agencies. Early in the pandemic, when testing was not readily available and community spread was present but not yet recognized, it is likely that, in some areas, patients with underlying disease and poor health may have died from undiagnosed COVID-19 infection. Other regions, the ones that responded to the outbreak by developing widespread testing, might be swabbing every decedent regardless of the circumstances of death, either as a public health screening program to gather data on community spread, or in order to protect morgue workers from infectious disease exposure during an autopsy.

Regardless of the availability of testing at their disparate death investigation agencies, medical examiners and coroners across the country are guided by the for death certification. A death certificate has two sections where the doctor who investigated the case will write the cause of death. Part I is the underlying disease or injury that starts the lethal sequence of events. Part II is for any other underlying conditions that the decedent had that made the death more likely.

The NVSS guidelines state, "If COVID-19 played a role in the death, this condition should be specified on the death certificate. In many cases, it is likely that it will be the underlying cause of death, as it can lead to various life-threatening conditions, such as pneumonia and acute respiratory distress syndrome (ARDS). In some cases, survival from COVID-19 can be complicated by pre-existing chronic conditions, especially those that result in diminished lung capacity, such as chronic obstructive pulmonary disease (COPD) or asthma. These medical conditions do not cause COVID-19, but can increase the risk of contracting a respiratory infection and death, so these conditions should be reported in Part II and not in Part I."

So, pathologists don't certify deaths as due to COVID-19 based solely on a positive nasopharyngeal swab. We get a clinical history of shortness of breath, chest pain, fever, cough. Yes, it is possible that someone could be an asymptomatic carrier and die of heart disease -- but in those cases we would certify the cause of death as heart disease and document the COVID-19 infection as a significant contributing condition, for several reasons.

Number one, COVID-19 can affect the heart (via myocarditis, pericarditis, or the formation of microthrombi). Number two, it's possible that the death may not have happened without the stress on medical resources caused by the pandemic. That's one of the reasons why the death toll in Italy is so bad -- their otherwise excellent healthcare system was grievously overloaded by a huge wave of COVID-19 patients. People who would've survived heart attacks during normal times died without medical intervention because they couldn't make it to the hospital or because the hospital couldn't treat them in time to save them. On some level it may be true that some natural-manner deaths being attributed to the virus could be seen as inflating the official COVID-19 numbers, but a failure to acknowledge and examine the pandemic's effect on the diagnosis and treatment of other natural deaths would also be problematic from a public health perspective.

To quote Dr. Ed Donoghue, a forensic pathology colleague at the Georgia Bureau of Investigation, "No matter how these deaths are currently being attributed, after this pandemic terminates, an excellent approximation of the true fatality rate of COVID-19 deaths can be made by the calculation of the excess mortality for the period. This calculation was very helpful during the . Almost certainly, because of the scarcity of testing and other reasons, we will find that the number of COVID-19 deaths has been grossly underestimated." The final death toll is going to depend on multiple factors: the density of the population; availability of testing; genetic factors (both host and virus); the public health response; and the robustness of the healthcare system.

A soldier in the heat of battle can't think strategically about the outcome of the wider war. The death toll of COVID-19 is not going to be accurate until epidemiologists and statisticians have time to crunch the numbers. But the excess stresses on our healthcare system are clearly evident in countless firsthand reports from emergency rooms and ICUs in our hardest-hit regions. The challenges of formulating a real-time body count must not be offered as an excuse to abandon or dial back the mitigation measures that we know are working to keep whole populations alive and safe. We are slogging through a slow, brutal, worldwide mass-fatality event. Whatever the final tally, it will be a terrible one.

, is a forensic pathologist and CEO of PathologyExpert Inc. Her New York Times bestselling memoir, co-authored with her husband, writer T.J. Mitchell, is . They've also embarked on a medical-examiner detective novel series with , now available from Hanover Square Press.