[Co-author of this article is Ronald E. Cossman, Ph.D., a Research Professor and Research Fellow at the Social Science Research Center at Mississippi State University. He also directs the Mississippi Center for Healthcare Workforce. His work focuses on the intersection of socioeconomic factors, geography and health in Mississippi, the South and the nation. His work has been funded by NIH, HHS, EPA, the Annie E.Casey Foundation and the Mississippi Department of Health. His PhD is in geography from the University of Colorado, Boulder, and his Masters is in Demography and Population Studies from Florida State University.]
Given that the peak of the initial surge in Whatcom County is approximately two weeks away, we believe any discussion of scenarios designed to ease containment measures should consider the number of unconfirmed, positive cases present in the county.
In Iceland, a country with widespread virus testing, some 50% of those who tested positive for COVID-19 were asymptomatic, in other words, feeling no symptoms of the virus. ( In the United States, without widespread testing, the director of the CDC estimates the number of asymptomatic individuals may be closer to 25%.
One difficulty in assessing the prevalence of the virus is that incubation—the time between initial infection and showing symptoms—appears to average 1 to 14 days, but can take up to 24 days. )An early study in China, published in Science, found that four out of five people with confirmed COVID-19 had likely been infected by people who didn’t know they had the virus.
Due to this lag time, the number of people who are unaware they have the virus, but are still able to infect others, suggests that containment measures need to be carefully evaluated before being relaxed, much less removed entirely. To put a number on this, we estimate that there are currently 1,973 people in Whatcom County who are unconfirmed, but COVID-19 positive.
Using the current estimates (found here) that each infected person can infect between 1.5 and 3.5 others, these unconfirmed positive people have the potential to infect between 2,960 and 6,906 others, who in turn could infect between 14,799 and 34,531 others, and so on. Obviously, if the containment measures are relaxed too soon, a second surge of cases could develop. If the containment measures remain in place longer than necessary, our economic and social well-being will be diminished needlessly.
To achieve this number of unconfirmed COVID-19 cases, we combined information from three sources. The first source is from information for the U.S. as a whole, including the number of confirmed COVID-19 cases and the number of deaths due to COVID-19 among those same confirmed cases. Our second source is an estimate of the “case fatality rates” from a study in Germany, and the third source is an estimate of this same fatality rate from South Korea.
The methodology used stems from a long-established method employed by demographers to estimate a population in the absence of a census count, known as the “censal-ratio method.”.
By dividing the case fatality rate found in the German study (0.004), into the number of COVID-19 deaths in the U.S. (18,559), we obtained an estimate of 4,639,790 unconfirmed positive cases in the U.S. We then divided this number by the number of confirmed COVID-19 cases in the U.S. (492,416) to find the ratio of unconfirmed to confirmed cases according to the numbers Germany found (9.4). We repeated these steps using the case fatality rate reported from S. Korea (0.00670), which led to a ratio of 5.6 unconfirmed positive cases in the U.S. By simply averaging these two ratios we get an estimate of 7.5 unconfirmed, positive COVID-19 cases for each confirmed case in the U.S. Multiplying 7.5 by the number of confirmed cases in Whatcom County (263), yields our estimate of 1,973 unconfirmed, positive cases.
Comments by Readers
Wynne Lee
Apr 14, 2020Excellent insights, thanks.
Fivethirtyeight.com has another good post today - in easy comic form - on why modeling is so hard, resulting wildly different guesses about possible outcomes. https://fivethirtyeight.com/features/a-comic-strip-tour-of-the-wild-world-of-pandemic-modeling/.
As the old Harry Belafonte song goes, “It’s clear as mud but it covers the ground”. The muddle lets anyone claim anything they most like, fear, want to manipulate public opinion with, make $ from, etc.
David A. Swanson
Apr 14, 2020“Mud” is too often associated with complex models. Arguably the best-known forecaster in the world today is J. Scott Armstrong. With Kesten Green, he wrote “Simple versus Complex Forecasting: The Evidence (Green and Armstrong, 2015), an article that suggests complex models remain popular among: (1) researchers, because they are rewarded for publishing in highly-ranked journals, which favor complexity; (2) methodologists, because complex models can be manipulated to provide support for the plans of decision-makers; and (3) clients, who may be reassured by incomprehensibility.
Green and Armstrong (2015) also found no evidence that complex models are more accurate than simple ones.
Reference
Green, K. and J. Armstrong (2015). “simple versus complex forecasting: The evidence.” Journal of Business Research 68: 1678-1683
hilary cole
Apr 16, 2020This is what this shut down is costing: “36,000 people die from every 1% increase in unemployment, according to a 1976 study by Harvey Brenner of Johns Hopkins.
Political Economist Toby Rogers, PhD, calls them them “deaths of despair,” and they include heart attacks (50%), suicide, alcoholism, homicide, mental health and prison issues.
42 further studies have corroborated that unemployment kills a lot of people, including a meta-analysis in 2011 showing that unemployment increases mortality rate by 63%.
Since that study was done, the U.S. population has increased by 60%. So I’ve adjusted the number accordingly:
That’s 57,600 deaths per 1% rise in unemployment.
Those who believe that the economic shutdown is warranted are using the “false dichotomy” logical fallacy that we’re choosing “lives over money.” Nothing could be further from the truth.
This is NOT a binary question (“lives versus money”). We’ve always had OTHER options than destroying our economy. Good ones.
Options used by other countries in far better control than we are, in our outbreak that has killed 6,600 Americans and 57,000 worldwide.
Herd immunity, if a majority of us were exposed to this virus (which we will be, anyway, if we haven’t already been), would make us immune for life.
And, the evidence shows most of us “get” the virus with cold- or flu-like symptoms, or no symptoms at all.
If our March unemployment rate of over 18% equals 1,036,800 U.S. deaths, according to the original study, supported by dozens of others—
—we are, then, taking a terrible approach, economically AND in terms of public health.
The unemployment rate will continue to skyrocket in the coming two months of “lockdown.”
Last week, ABC News and Washington Post released results of a poll showing 51% of Americans have already have their work hours or pay cut, by the shutdown.
Goldman Sachs did a survey released last week that 51% of the 1,500 small businesses surveyed will fail if the economy remains locked down for 90 days.So that figure of 1 Million+ U.S. resulting deaths will only go up, dwarfing what the predicted from COVID19.”
David A. Swanson
Apr 16, 2020Hola, Hilary Cole,
it looks like you are up to the task of spreading “fear porn” about the deaths and despair stemming from our economic system and the current condition it finds itself within because of failures in the current federal governent to stop this pandemic before it started. This was not the case with earlier intrusions of Ebola and SARS into the U.S. They were stopped in their tracks. It is a tragedy that the failure of our federal government has led us to the choice between death by virus or death by lack of work.
I trust that as you continue to disseminate your own gospel of “fear porn” you will be still be able to employ the internet from a safe and comfortable location and have access to all of the sources from which you have so painstakingly assembled the many facts carefully woven into your tract. On your next update you might mention that Spain dealt with the dilemma of death by virus vs. death & despair from joblessness by paying the unemployed their full salaries while remaining at home. Oh, I nearly forgot to mention that like all advanced economies with, of course, the exception of the U.S., the Spanish have universal healthcare.
hilary cole
Apr 21, 2020Hi David Swanson,
Here is a story: KEEPING THE TIGERS AWAY
A man is walking by another standing on the road shaking his sword. “Why are you doing that?,” the man asks him. “To keep tigers away,” the other answers. “But there are no tigers here!,” the passer-by exclaims. “See, it works!”, is the reply.
Your fear mongering predictions have not materialized, SO now you are saying, ‘See! This isolation, distancing, and face masks have defeated corona virus!!!!” The magic sword that has kept the tigers away!
David A. Swanson
Apr 21, 2020Hilary Cole,
You appear to be more interested in making political points in the context of personal attacks than spending the litttle time it takes to comprehend what a baseline forecast is and the role it plays within an impact analysis framework.
I trust you will be at all of the mass demonstrations against containment measures, always without a mask and ignoring social distancing guidelines, standing tall and proudly showing the rest of us your commitment to the belief that your magic sword will keep you safe from COVID-19. As Judge Jeanine famously said in one of her TV courtroom shows, be sure to let us know how that works out for you.
Ryan M. Ferris
Apr 21, 2020Below are some links that discuss percentages of ‘asymtomatic’ (and otherwise) COVID-19 cases in various sample populations. The projected infection rates vary greatly. I am impressed that both the small German study, Aircraft Carriers, Boston Homeless are showing two digit infection rates. The Santa Clara study is very small in comparison to nearly 2M that live in that county. Still its assay show rates of infection much higher than expected. Personally, I project a minimum of 60% world wide exposure by the end of year without either treatment or vaccine. This level of contagion will isolate those who have attempted to shelter in place. There won’t be anywhere to hide.
https://www.wbur.org/commonhealth/2020/04/14/coronavirus-boston-homeless-testing
https://www.news18.com/news/world/in-german-town-of-gangelt-blood-samples-of-residents-show-14-now-immune-to-covid-19-report-2572279.html
https://news.usni.org/2020/04/14/950-sailors-now-have-covid-19-2nd-uss-theodore-roosevelt-sailor-in-intensive-care
https://news.usni.org/2020/04/15/two-u-s-sailors-on-french-carrier-charles-de-gaulle-test-positive-for-covid-19
https://www.cebm.net/covid-19/covid-19-what-proportion-are-asymptomatic
https://doi.org/10.1101/2020.04.14.20062463 Santa Clara County (Stanford) Assay study
One thing to keep in mind is that there may be no immunity to this disease, not in small part because there are at least three different variants of SARS-CoV-2 running wild and unchecked across the globe:
https://www.pnas.org/content/early/2020/04/07/2004999117
https://www.theguardian.com/society/2020/apr/20/studies-suggest-very-few-have-had-covid-19-without-symptoms
Quite possibly, these three variants could engage in reassortment and/or recombination and continue the evolution of SARS-CoV-2. Without working medical treatments (of which we currently have none), we will be like barking dogs behind a fence, our masters throwing us dog biscuits soaked in 80 proof alcohol: “Don’t touch your face”, “Wash your hands”, “Shelter in Place”,“Build more ventilators”, “Stay six feet apart”, “Cloth masks” and numerous other tidbits which really are not doing anything but prolonging mass die off especially of older and the immune compromised. I am OK with following these guidelines, but a ruined economy will eventually be controlled by desperate men with guns. And there is plenty of this the world over and in most big cities in this country. At some point, all political decisions are cost benefit analysis weighed in lives lost. We have a mandate for our species as a whole to preserve civilization and a non bankrupt economy for those generations still with reproductive potential. Those are harsh words but these are harsh times. Tough decisions have to be made in face of a disease this virulent for which we do not have or may not ever have any cure or treatment.
David A. Swanson
Apr 21, 2020You might want to take into account “timing” in a revised argument because it is the key element in the containment strategy that is absent from your analysis. Containment measures are meant to spread cases out over time, not stop them. The idea is to hold down the potential for huge waves of patients to crash into the healthcare system at the same time, overwhelming it. By stretching out over time the number of people who become sick, instead of having the same number show up all at once, the caseloads also are stretched out. This forestalls, if not prevents, the severe triaging that Italy had to employ and also serves to maintain both the safety of healthcare workers and the supplies they need. In addition, slowing down the rate of infection will give us more time for effective therapies and vaccines to come online, saving more lives.
Put another way, suppose you have a dirt driveway that is 20 feet wide and 40 feet long and you decide to have a concrete driveway installed that is 2” thick and that you believe you know enough to supervise the operation. Would you tell the crew to pour the 5 yards of concrete or so needed for the job all at once for in measured amounts over time, allowing the crew to cover your driveway evenly at the desired thickness? The correct choice is obvious in such a “concrete” example, but I guess it is less obvious in a discussion about a virus less than millionth of an inch long embedded in the “abstract” concept of time.
Ryan M. Ferris
Apr 21, 2020Deaths aren’t measured or poured in concrete unless you are the mob. We aren’t really slowing the rate of infection or deaths now. There’s no real statistical evidence of this. SARS-CoV-2 is so damn resilient and infectious that our best efforts are being thwarted; literally mocked by the virus in places like New York. Most victims are actually just dying of pneumonia in their homes and not being recorded as COVID19 because the nations coroners have no test kits for the dead. Triage is an effective policy for such numbers and it is being used now. You save the young and the reproductive generations. The rest you ship to hospice or just tell them to expire at home. Letting the economy die sacrifices the economic future of the survivors for those that are just waiting in line to die. Life isn’t fair. But really, given all the money we have spent on Virology and virological testing, we should have been prepared for this. No western nation was and Asian victories are starting to look suspect due to the enduring and perhaps latent nature of the virus.
The idea that we are ‘flattening the curve’ is just more BS. It only works if you have a treatment at the end of your flattening efforts. Otherwise you are just bankrupting the economy; literally bleeding to death healthy workers, families, children without any purpose or end.
David A. Swanson
Apr 21, 2020I won’t be calling on you to work on my driveway.