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When Did COVID-19 Arrive and Could We Have Spotted It Earlier?

— A forensic pathologist investigates

Last Updated May 12, 2020
MedpageToday
A US flag with the stars replaced by coronavirus icons

In the last few weeks, we have learned a lot more about the timeline for the emergence of the novel coronavirus disease COVID-19 in the United States. California's Santa Clara County discovered that SARS-CoV-2, the virus that causes COVID-19, was responsible for the , an apparently asymptomatic 57-year-old woman who worked in Silicon Valley and who died on Feb. 6 of . Since then, Santa Clara County health authorities have reclassified nine deaths that were not initially considered COVID-19 cases as being due to the pandemic. Patricia Dowd's death is currently being cited as the first known case of a COVID-19 death from community spread in the U.S.

But Dowd's demonstrates that this "Patient Zero" assumption is almost certainly wrong -- and weeks off the mark.

Patricia Dowd's heart weighed 290 grams -- a normal size -- and was of normal shape. The autopsy showed that its muscle tissue was damaged badly enough that the left ventricular wall had torn open. A heart will typically suffer this type of severe damage in the setting of high blood pressure and high cholesterol, in patients who have had a prior myocardial infarction. Dowd was overweight, with a BMI of 31, but she had no cholesterol in her coronary arteries and no history of high blood pressure or heart disease. Yet her heart ruptured. Healthy hearts don't do that.

Microscopic and molecular studies during Dowd's postmortem investigation uncovered evidence of infection by SARS-CoV-2 in her heart muscle cells. Her myocardium had "mixed chronic and acute inflammation... and early fibroblast response." The inflammatory response in viral myocarditis is insidious, and it is slow. Heart muscle tissue doesn't break down and get weakened to the point of rupture until weeks after it's first been infected. Given the time course of COVID-19 (>90% of people are symptomatic within 2 weeks of infection, with fatalities occurring on average 2 weeks after that), Patricia Dowd was likely infected with COVID-19 in early January -- when, as it turns out, her being laid up with flu-like symptoms. Dowd was a frequent traveller, and she worked in a Silicon Valley company where people went back and forth from . The Chinese government claims that the Wuhan virus was first discovered there in November, but this timeline has been undermined by reporting that Beijing also tried to .

Is it possible, then, that the COVID-19 virus was on U.S. soil earlier than January -- maybe even as early as November?

It's not just possible; it's likely.

Is there a way to find out?

There is.

Epidemiologists can get it started. They need to focus on excess mortality (higher than the seasonal averages for past years) in U.S. regions that have close industry relationships with Wuhan: Silicon Valley (which includes Santa Clara County), metropolitan Seattle, the Route 128 corridor outside Boston, and tech hubs in New Jersey and New York. We may find that these areas had elevated excess mortality in late 2019 -- cases that will not have been recognized as deaths due to COVID-19. They will have been middle-age, elderly, or infirm people with pre-existing conditions who died in hospitals. Their own doctors will have signed their death certificates as due to natural disease, and will not have reported the deaths to the local medical examiner, because these deaths will not have been extraordinary in any way. As the cause of death, these death certificates will list ARDS or pneumonia in the presence of underlying medical conditions such as COPD and hypertensive cardiovascular disease. They might list pulmonary emboli and other thrombotic manifestations of COVID-19 infection without mentioning the virus at all; at the time those death certificates were filed, the pathophysiologic link between SARS-CoV-2 infection and thrombosis was not understood, and would not have been recognized. These ordinary death certificates could reveal the vanguard in the greatest natural killer of Americans in over a hundred years -- invisible as such at the time it arrived.

Our technology sector can also play a critical role in this retroactive public health investigation. Performing antibody testing on workers at companies closely linked to China, and interviewing them to find out whether they were sick around the holidays, might help identify people who were exposed in January, or earlier.

Medical examiners save samples of blood, for toxicology and identification purposes, from all our cases. We could test them: COVID-19 on blood are both sensitive and specific. Furthermore, hospitals typically hold surgical pathology tissue specimens from patients who had bronchoscopies and biopsies. They could send these samples from November and December to the CDC for analysis of COVID-19 RNA, a test even more specific than the antibody assays.

By combining all these efforts, we can hammer down a much more precise Patient Zero date than we have achieved with our current level of guesswork and assumption. It's critical that we undertake this effort right now. We may have to reclassify some deaths as due to COVID-19, necessary to an accurate picture of the events that brought the virus to this country; when exactly it arrived and how many people it has actually killed. Public health experts rely on these numbers to advise politicians about the best way to manage this national emergency.

The revelation that COVID-19 killed Patricia Dowd in early February pushes back our assumption about the onset of community spread in the U.S. by a month. More and earlier cases will emerge, and we are going to find out that this date is probably wrong, too. If we can learn from the virus deaths we missed in December or January in our earliest hotspots, other regions of this country where COVID-19 has not yet infected or killed anyone can be on the lookout to make sure they don't make the same mistakes and miss their own first cases. They can start surveillance swabbing of decedents, as the . They can network with epidemiologists making excess death assessments prospectively, and alert local medical examiners and coroners that deaths being certified by clinicians as cardiac events, pneumonias, and fatal thrombi might be failing to reflect and record COVID-19 as the underlying cause of death. It may be a good idea for local public health agencies to start tracking excess mortality on a regional basis routinely, the way we monitor tremors along known fault lines to alert us of impending earthquakes.

Forensic pathologists identify public health hazards that kill people. We step up and we speak out to stop preventable deaths from happening. By investigating our failure to identify community spread of COVID-19 before it killed Patricia Dowd in February, we can help the CDC and local public health departments all over our country develop a surveillance system to identify and isolate the next novel contagion before it follows in the path of COVID-19.

, 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.