It’s Elementary — More Americans Have Been Infected by the Coronavirus than Previously Thought

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Matteo Galimberti/ Image used under license from

In Arthur Conan Doyle’s The Sign of the Four, Sherlock Holmes rebukes Watson after the good doctor accuses him of engaging in mere guess-work by tersely responding: “No, no: I never guess. It is a shocking habit — destructive to the logical faculty.” Holmes then patiently (and perhaps a bit condescendingly) walks Watson through the pieces of data and steps of deduction that led to his correct conclusion.

If Holmes were alive in 2020 and working on The Case of the COVID-19 Pandemic, he undoubtedly would be intrigued by four critical pieces of data that were made public over the past few days:

· On April 17, health officials in Santa Clara County, CA released findings from an antibody study that concludes far more people probably have been infected with COVID-19 than confirmed cases would indicate. Specifically, the study estimates that between 2.49% and 4.16% of county residents had been infected by April 1. That translates to between 48,000 and 81,000 people — 50 to 85 times more than the official confirmed case count of 956 people.

· On April 20, the University of Southern California and the Los Angeles County Department of Public Health released preliminary results of a different antibody study. This study indicated that somewhere between 221,000 and 442,000 residents of L.A. County had been infected by early April. That is 28 to 55 times higher than the 7,994 confirmed cases in the county.

· On April 22, the CDC confirmed that two people infected with the coronavirus in California died at least two to three weeks before what was thought to be the first U.S. death from the disease. This means that community spread of the virus was occurring MUCH earlier than health officials and epidemiologists suspected.

· On April 23, the New York Times shared data-modeling results from researchers at Northeastern University, which looked at five major U.S. cities (Boston, Chicago, New York, San Francisco, and Seattle). On March 1, those cities had 23 confirmed cases; however, the researchers’ model indicates there may have been at least 28,000 cases in those cities — over 1,200 times the confirmed amount!

What makes these data points so powerful is that they are all from states that implemented some of the earliest and strictest social-distancing measure in the country. So if the virus had spread that significantly in some of the most proactive states, what might the community spread look like in states that engaged in social-distancing measures much later?

That question can’t be fully answered yet. But if we extrapolate these studies’ findings nationwide, the final numbers are staggering.

As of April 23, there are approximately 850,000 confirmed cases in the United States. Using the low end of the USC study (28 times the confirmed cases) that would mean almost 24 million Americans have been infected by the coronavirus. If we use the upper end of the Santa Clara study (85 times the confirmed cases) that would mean over 72 million Americans — 1 in 5 — have been infected. And if the Northeastern University modeling is even remotely accurate, it’s not hard to imagine that nearly every American has been at least exposed to the virus.

The good news is that antibody testing is ramping up. So, we will have more precise numbers soon.

Until we do, we’ll have to be careful not to draw any false conclusions. After all, as the great detective cried out in The Adventure of the Copper Beeches: “Data! Data! Data!…I can’t make bricks without clay.”

But here’s a little more clay with which to build.

The CDC has identified the 2019–2020 flu season as one of the worst in decades. And now that we know the coronavirus was present in the United States much earlier than expected, it is very possible that many of the flu diagnoses in January and early February were in fact cases of coronavirus — a possible confusion the CDC admits on its own web site when it notes that “elevated influenza-like-illness is likely related to COVID-19.”

This possibility that many sick individuals and even deaths were misdiagnosed in January and February was further reinforced by Eric Topol, a geneticist, researcher, and director of the Scripps Research Translational Institute in an interview with the Washington Post on April 22:

“How many of those were presumed to be flu or pneumonia when they were actually COVID-19?”

If Topol, the CDC, the Northeastern University researchers, and these early antibody studies are correct, then it is highly probably that tens of millions of Americans were infected by the virus PRIOR to the implementation of social-distancing measures. And if that’s the case, one day we may have to admit that those measures — and the resulting economic meltdown caused by them— were the proverbial case of “closing the barn door after the horse has left.”

But as the great detective warns us in A Scandal in Bohemia: “It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” Consequently, we’ll need to see what widespread antibody testing and subsequent modeling reveals over the next few weeks and months.

One thing is certain, however. For epidemiologists, health officials, and data-modeling experts, “the game is afoot!” (The Adventure of Abbey Grange)

President of Marathon Leadership, LLC — an organizational and leadership consulting firm based in Thornton, CO. Learn more at

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