Antibody Tests in Colorado Highlight the Huge Gap Between Confirmed COVID-19 Cases and Total Infections

Clarifying the prevalence and lethality of the virus will require wide testing that goes beyond a single rural county.


The latest results of mass antibody testing in San Miguel County, Colorado, suggest that 1 to 2 percent of the local population has been infected by the virus that causes COVID-19.* The early results from the program, the first of its kind in the United States, underline the point that official counts of COVID-19 cases, which are limited to people who are sick enough to be tested for the virus, greatly understate the total number of infections.

United Biomedical, a company based in Hauppauge, New York, is collaborating with the San Miguel County Department of Health and Environment to test all 8,000 or so residents of the county. So far the company has drawn about 6,000 blood samples, although analysis has been delayed because of limited laboratory capacity.

As of today, the county had received 2,583 test results, of which 17 were positive and 43 were borderline.* Assuming that the initial samples are representative of the county's general population, that suggests between 0.7 percent and 2.3 percent of residents have been infected by the COVID-19 virus, including people who had mild or no symptoms.

Applying those rates to the U.S. population implies 2.3 million to 7.5 million infections nationwide, compared to about 700,000 confirmed cases so far.* There is reason to think the nationwide prevalence is higher than the rate in San Miguel County, a sparsely populated area of southwestern Colorado with 5.7 people per square mile, compared to the U.S. average of 94. Even in Telluride, the county's seat and biggest city (with about 2,500 residents), there are 1,120 people per square mile, compared to about 4,000 in Dallas, 4,700 in Denver, 12,000 in Chicago, 19,000 in San Francisco, and 28,000 in New York City.

Leaving aside differences in population density, the San Miguel County results suggest that the true number of infections in the United States may be three to 11 times as high as the number of confirmed cases.* Similarly, researchers at the University of Gottingen in Germany recently estimated that the official U.S. count as of March 30 excluded more than 90 percent of infections. Australia's chief medical officer likewise suggested this month that the global case tally was off by a factor of about 10. A study based on unusually high numbers of influenza-like illnesses, by contrast, estimated that official COVID-19 counts as of late March included just one out of 100 symptomatic cases in the United States.

Virus tests of volunteers from Iceland's general population have come up positive about 0.7 percent of the time so far. That result, which is similar to the low-end estimate for San Miguel County, is based on nearly 24,000 tests in a country with a population of about 340,000. It does not include people who were infected but no longer carry the virus, who would be identified by antibody tests.

Iceland reported its first confirmed COVID-19 case on February 28, more than a month after the United States did. And unlike the United States, Iceland has combined wide testing with aggressive contact tracing and targeted quarantines. It therefore seems likely that the prevalence of infection is higher in the United States.

The actual prevalence of the virus is crucial in estimating not just the risk of infection but the odds that it will kill people who catch it. Although the overall fatality rate is obviously relevant in deciding how to fight the epidemic, current estimates cover an absurdly broad range because we have no idea how many people have been infected. "Fatality rates based on comparing deaths, which are relatively easy to count, to infections, which are not, almost certainly overestimate the true lethality of the virus," The New York Times notes. "Health officials and epidemiologists have estimated there are five to 10 people with undetected infections for every confirmed case in some communities, and at least one estimate suggests there are far more."

Clarifying these issues will require mass testing that goes beyond a single rural county in Colorado. The Centers for Disease Control and Prevention, which helped engineer the testing fiasco that has left us ignorant of basic facts about the COVID-19 epidemic, recently began promising "wide studies of community transmission" based on antibody tests.

[*This post originally used test results that had been reported as of Tuesday; the numbers have been updated to reflect results reported as of April 17.]

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  1. Also in Santa Clara. Estimating up to 85x more residents had covid. Meaning this lockdown was not needed.

    1. Yep. Not surprised at all by these results.

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    2. Not really…

      “*UPDATE: One caveat is that a rough calculation applying the Santa Clara infection fatality rate to New York City’s 11,000 COVID-19 deaths would imply that essentially all of city’s residents have already been infected with the coronavirus. This seems implausible.”

      1. Umm… I ready addressed that in the other thread. Stop taking Ronnie as an actual authority.

    3. It’s pretty common knowledge in California that the virus was here months earlier than officially declared. Lots of people already lived through this, with moderate to severe flu-like symptoms. Californians have better immunity because they’re less obese and get more sunshine, and it doesn’t spread as fast because there’s less public transportation.

    4. Having read the study, there is no conclusion that the lockdown was not needed. On the contrary, the study specifically states that the measures were needed to control the spread of the virus so that the health service can cope with the influx of patients. Remember, regardless of the percentage of fatalities relative to the number of cases and the similarity of that percentage to that of the common flu, the R0 number for Covid-19 is much higher than that of the flu. That is to say, Covid-19 is significantly more contagious than the common flu. This accounts for the high number of hospital admissions and total fatalities, which from the perspective of the health system in managing patient flow is the most important statistic.

      1. Botticelli imagines the lockdowns were needed, thus the lockdowns were needed.
        Fuck you, totalitarian scum

  2. I really do not understand why mass testing is needed. Even with the information we already have, it is clear this virus is not a serious medical issue for 99% of people. Further, more testing does not mean there is going to be more effective treatment.

    Let’s assume tens of millions of people are infected. What is going to change in our approach? I just do not see the point, and people covering this issue seem to take it for granted that more information is always better, even if we cannot do anything with that information.

    1. Because… testing everyone extends the lockdown.

      1. Bingo.

        Mass testing is a rhetorical threshold to justify draconian government crackdowns and to perpetuate the illusion that we are capable of controlling an uncontrollable variable in our daily existence that places almost nobody at any serious risk.

      2. More likely scenario is because scientists want perfect data even though it’s impossible. And, of course, the government is happy to extend their emergency powers in the name of getting that perfect data, which they can never deliver.

        Making 350 million tests, at least, in time for it to matter was never in the cards let alone distributing, administering, and reading those tests.

      3. People love stats, and more testing means more opportunities to track and document more people’s every movement

    2. Power.

    3. Testing tells us where on the curve we are, and therefore we can decide if we need to flatten it and for how long. Granted, it looks like those questions can already be answered for 90% of the country, but even a couple weeks ago it was less certain.

      1. Assuming there is one uniform curve, and there clearly is not. And if it is cyclical, and seasonal, then who cares about the curve? This whole notion that testing is absolutely necessary seems really to be a quite tenuous justification for perpetual lockdowns.

        1. Well, if we’re 30-60 days further along each individual curve, that means we don’t have to worry about the healthcare systems getting overwhelmed.

          Of course, we would need honest officials to make the right calls with such data, and I’m not sure we’re there.

          1. I have my doubts as well.

      2. Testing the residents of a ski county, while not testing the thousands of tourists who went through will tell us one of two things applicable to the rest of the country: Jack & Shit. And it ain’t Jack.

        Seriously, the attempts to scale up these numbers to the rest of the country are similar to the ham fisted numbers that Twits have been using to shame everyone into their homes.

        1. ^ This. A ski resort community where jet-setters go to vacation is probably not the perfect test case scientists are looking for. It does tell us that people who fly into Denver don’t do a whole hell of a lot before heading into the mountains, though.

          1. Yeah, Telluride is definitely not a representative population.

      3. You flatten the curve too much and it extends into the next cold and flu season and the shutdowns never end and the state and all the businesses and people in it go broke. Better to get it over with sooner.

    4. I agree. What is the plan, 330 million tests a day? Because unless you test everyone, simultaneously, you don’t really know too much about the next day.

      Testing for antibodies in 4 or 5 different areas, twice, should be enough to determine scope and speed of exposure.

      All info thus far suggests the denominator is much higher than even the high estimates and the hysteria is baseless.

      1. If only they treated the notion of testing the way they treat political polling. What ever happened to representative sampling?

        “Fuck it. It has to be everyone. This nice company is going to do it, for $30 billion dollars.”

        Oh, there it is.

    5. Mass testing is imperative and the only way to understand how to end this. What many of these commentors don’t want to understand is that without the shutdown you would have at least 100 times as many people in the hospitals and literally dying in the streets. The virus spread is exponential. The world doesn’t have enough resources to deal with all of the sick people we need time to both create more protection supplies and hopefully develop a cure, medicine that helps and a vaccine. It’s a simple concept.

      1. The virus will end itself like all the other viruses, or come back every winter. People at risk should practice social distancing, and maybe get a shot once there’s a vaccine. We don’t have mass testing for the flu or SARS or H1N1 or the common cold.

      2. Shelter in place orders effectively infected millions of household. If your mom had covid and you lived with her for 4 straight weeks, you’re also infected.

        In CA people went from sitting 4 hours in traffic everyday alone to being QTed at home for 4 weeks. But the hospitals here aren’t overwhelmed. If the virus spread and killed with light speed the couple weeks most people in the state went about their lives without masks AFTER statewide shelter in place should’ve been enough to blow up every hospital.

        I mean, do you SEE social distancing in places like Walmart? You think patrons there will never touch anything? Do you socially distance yourself at home at all times? Reagan’s Star Wars program might intercept some nukes headed our way, but if there’s a hundred headed our way most will hit us. That’s what this situation is.

        Korea shutdown a hot zone way before NY and wearing masks is ingrained in their culture. Testing is only part of the picture. What’s America going to do after massive tests in all 50 states, over a 380 mil people? Track them all on their phones like Korea, over a land that’s something like 4th or 5th largest in the world?

        Are people not able to see maps? We have chunks of mostly spread out lands that are in manageable situation. Oh no, but in 4 weeks they might be the next Italy!

        1. We are far too tolerant of people like Jay, who have destroyed the lives of tens of millions of people.
          This is war, and it’s war being waged on all of us by people like him.
          Time to fight back

    6. More lock downs are not needed for more testing. More testing, however, may reveal that the virus was first introduced, INTENTIONALLY, in New York. then spread to other areas. This may explain the bizarre China claim that the US Army introduced it to China; because CHINA KNEW it was first introduced in New York.

  3. Fuck you, no testing.

  4. Hopefully it will let me post a link:

    Facilities anticipating ICU bed shortages in the next week: Four.

    This will probably be used to justify that the lockdown was brilliant, when in fact it is more likely that most people were already infected before the lockdown in late March.

    1. The brilliant part about unfalsifiable claims is that you can be completely wrong, and still claim complete vindication. At this rate, the science is so shoddy, stating that Zeus stopped the virus dead in its tracks is just as tenable a claim.

      1. Yeah, this seems true. They made an outrageous claim and followed it up with ‘we fixed it, which is why out claim didn’t come true’.

        Can’t really prove them wrong, even though no one will notice they couldn’t prove themselves right.

        Burdens of proof, how the fuck do they work?

    1. Interesting. I suppose both things can be true, however. The virus evolved in animals, and was being studied in a Wuhan lab (from which was leaked).

      1. “Everything we thought we knew about the beginnings of the coronavirus pandemic could be wrong.”

        Don’t you love hyperbole like this? We know that Wuhan was an early epicenter, so if the virus didn’t originate there, it only slightly changes the details. Not EVERYTHING. And that’s the fucking first line int eh story.

        I wish people were intelligent enough to know better than to do this.

        1. “…And that’s the fucking first line int eh story…”

          If they can’t offer DRAMA, why write headlines?
          Well, except to mis-inform…

    2. I like their other story about how coronavirus is spread through farts.

      1. It’s not?

    3. Should probably take UK news with a pretty massive grain of salt. Especially the Daily Star.

    4. Personally I prefer that sources: Coronavirus spreads through farts

      course nothing really beats their investigative photojournalistic research into titties.

  5. I don’t think you’re allowed to be making these arguments.

    1. Not really…

      “*UPDATE: One caveat is that a rough calculation applying the Santa Clara infection fatality rate to New York City’s 11,000 COVID-19 deaths would imply that essentially all of city’s residents have already been infected with the coronavirus. This seems implausible.”

      1. Californians have better immune systems, since they get more sunshine and are less obese. And viruses don’t have mass public transportation to spread on.

      2. Supposition vs data. More of these serological studies will come out, we will get a better picture of the true lethality. My prediction is that it is too widespread to contact trace, that we will not be able to eradicate it unless it fizzles out on its own, that we need some near term protocols to end the lock downs, and that ultimately we will just have to live with it.

  6. Although the overall fatality rate is obviously relevant in deciding how to fight the epidemic, current estimates cover an absurdly broad range because we have no idea how many people have been infected.

    Thank goodness our betters lit the economy on fire, threw $2.3 trillion gallons of gasoline on it then bulldozed it off a cliff just to make sure.

    1. and they’re getting ready to throw another couple of trillion on the fire.

  7. by the time mass-testing for all is implemented we’re going to be in the next cold/flu season and it won’t matter

  8. “The early results from the program, the first of its kind in the United States, underline the point that official counts of COVID-19 cases, which are limited to people who are sick enough to be tested for the virus, greatly understate the total number of infections.“

    How does this study reconcile with the fact that in areas which have limited testing are returning positives just over 10% of the time? If the population being tested is more likely to be infected, why are the positive results not higher?

    1. Limited testing means they only test the people who they think have it.

      And in those cases, they are still wrong 90% of the time, per your example.

      1. My point is: this random sample study says millions of people are infected, but the limited population samples show that the people believed to be infected are not, in fact, infected. That would seem to suggest that the prevalence of Coronavirus is not that high, wouldn’t it?

    2. I don’t know about other places – but CO has plateaued its testing now for about three weeks. I don’t know what the constraint is but it’s beginning to be a real problem. And the % of positives has grown from 10% to 25% in that time.

      1. Stuff your PANIC!!! flag up your ass, stick first, sit on it, and then fuck off and dies, you pathetic piece of cowardly shit.

    3. Because a lot of people get colds and flu at this time of year, duh.

  9. All of these studies in small, semi-rural or deep suburban populations are nice, but kinda irrelevant.

    Someone needs to wade through downtown London, Paris and/or New York and grab a cross-sectional cohort and find out what the real infection rate is. Because if we find out that New York is already 45% infected, we can pull the plug on this thing tomorrow.

    1. Just a reality check… does everyone know the name of the virus that causes the disease the WHO decided to call “COVID-19”?

      It’s SARS. Or, more specifically, SARS-CoV-2. The original SARS virus (now named SARS-CoV-1) just kinda died out in 2004. Now, prove to me that won’t happen with the Wuhan SARS that got loose in December?

      1. SARS 1 died out in large part because it was only contagious well AFTER symptoms appeared. Same with MERS to a degree. So it was very contagious in hospitals – but except for a couple of doctors who spread it outside those settings, it stayed there

        Once medical staff had PPE and made those hospital settings less contagious, that was it

        1. Stuff your PANIC!!! flag up your ass, stick first, sit on it, and then fuck off and dies, you pathetic piece of cowardly shit.

    2. Santa Clara county is not a deep suburb. It’s Silicon Valley, with high rise offices and 5 story apartment buildings and people eating at giant company cafeterias.

  10. I’m a little skeptical of the Santa Clara county results although, admittedly, I’ve not read the study to determine how effective their adjustments for what was likely a quite skewed testing cohort were.

    As I understand it, they advertised for people to be tested via Facebook so, right away, those tested had been filtered a bit – only active Facebookers would have been likely to even see the ads.

    Those participating also had to go to some effort and have access to private transportation to do so as the testing was held at three sites and was “drive through only” as I understand it.

    Who would go to the trouble to make an appointment, drive to the site, and get tested?

    I wouldn’t because it’s unlikely I’ve been infected (I don’t work outside the home, I don’t hang out in crowded public places very often, I always try to “disinfectant wipe” shopping carts, and I quickly dropped into hermit mode upon a suggestion of that being a good idea). Also, there’s nothing actionable I could do with the information anyway – we don’t know if having the antibodies infers immunity (and there’s some evidence it does not) so I wouldn’t start licking door handles and kissing strangers just because I had the antibodies.

    However, if my work or commute required that I interact with the general public regularly and perhaps in dangerous ways (such as healthcare workers, mass transit commuters, and retail workers) it might be a different story. I might bother to take the test because the odds of a “positive” (i.e., I had the antibodies) would be much higher. As well if I had the antibodies I might feel a little bit more comfortable with continuing to work at my job but if I tested “negative” I might decide to stop reporting to work in order to reduce the chances of eventual infection.

    So, I would think the “self selected” study group would more likely to have been exposed than the general public. On the other hand, of course, folks living at Petri Dish Meadows Retirement Home likely would have been excluded from the sample set for many reasons and they likely are more likely to have become infected with the virus at some point in time than the general public.

  11. “…Clarifying these issues will require mass testing that that goes beyond a single rural county in Colorado…”

    But not much more. Carefully designed testing regimes that cover a range of demographics, geography, density, and other factors decided by the experts can lead to extremely reliable estimates of for the population as whole. Ten or so samples of 5k-10k people each is more than enough. We don’t need to test millions of people to decide the prevalence question.

    1. No doubt. It’s sad but predictable that, for this particular exercise, the “SCIENCE DENIER!!!1!!” crowd is wailing that statistical sampling won’t work at all and the only way to have any idea where we are is to test every frickin person in the country. Because Somebody Somewhere Might Die or something.

  12. South Korea, who is touted for a good test program, tested 1% of their population. US testing rate has now exceeded South Korea. Of the bigger countries, 2.5% of population is max

    1. But if it saves just one life….

      1. The shutdowns are saving lives, no doubt — because highway traffic is greatly reduced. Fewer accidents. Even AllState is giving customers refunds.

  13. So you tested negative a week ago. Are you going to hug your granny today? swab for virus is a waste of effort for a highly contagious, rarely lethal virus. Only works on highly lethal outbreaks where containment is not impossible.

    1. Did you have a point, or just some bandwidth to waste?

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  15. The Centers for Disease Control and Prevention, which helped engineer the testing fiasco that has left us ignorant of basic facts about the COVID-19 epidemic, recently began promising “wide studies of community transmission” based on antibody tests.

    Mr. Sullum, I have a real problem with this characterization. It lacks context and it is wrong. And unfairly maligns the CDC. You imply the CDC deliberately fucked up testing, which to me is borderline slanderous. Where are your journalistic ethics and propriety?

    The CDC operated a surveillance based system, by design. Guess what? It worked. We did see evidence quite early that something was up. The first reported US Wuhan coronavirus case was January 19th, and first death was February 29th. Let’s use the first death as a reference point in time.

    The CDC co-ordinated the development, implementation and distribution of a surveillance based testing system to a national mass testing system in 45 days (3/1 – 4/15). That is correct…from a standing start on March 1, we have successfully created a mass testing system on the fly in the face of the largest global pandemic in a century in 45 days. Are you fucking kidding me? Engineered a testing fiasco? Get your head out of your ass Mr. Sullum, please. This is an astonishing feat for any country; and for the record, nobody else in the world has done it. The United States did. We are now able to implement mass testing to reopen our economy. This was a truly heroic effort by the CDC, private industry (they have been magnificent!), and academia (developing an array of testing types: saliva, swab, etc).

    There is plenty to criticize out there. I am more irritated with Congress at the moment. The Congress needs to pick up their fucking pace and actually get more useful things done and stop the petty political horseshit.

    There are a number of governors who have handled testing incompetently. Phailing Phil Murphy, governor of the People’s Republic of NJ is a poster child for crisis management incompetence. We currently have a 8-10 day delay in processing tests. Getting a test is problematic. And we are in the epicenter. The Governor and his Health Commissar (Judith M. Persichilli) have singularly failed when it comes to testing. Completely and utterly incompetent in addressing this crisis. I’d love to see an in-depth Reason article on this state level fiasco.

    I take exception to your slam on the CDC. It is short-sighted, and it is wrong. What we have seen in the last 60 days from the CDC is something that will be written about for a long time as a textbook primer on how to successfully deal with pandemics. The last two months has been the CDC’s finest hour. When you consider the scale and complexity of developing, implementing and then delivering a mass testing system for a country of ~330MM people in 3,147 counties contained within roughly 40,000 discrete zip codes….it is nothing short of miraculous that the United States did this in 45 days.

    1. I am expecting to see a lot of reactions like this from politicians and government officials over the next year. They will all be firstly looking for excuses for their actions or inactions. Then they will be telling us what a great job they did and how they saved the world.

      When total death statistics for the year come out that will be the signal for congratulating themselves on saving the world. This will be easy because its unlikely that the current death rate from Covid19 will change annuals deaths by much.

      Covid19 is a reality TV show. “The biggest pandemic for a century.” Where was the CDC in 1968, Hong Kong Flu, infected over 5 million world wide with over 1 million deaths. Where was the CDC in 1957, Asian Flu, infected at least 10 million world wide with an estimated 4 million deaths.

      It would be nice to think that organisations like the CDC will in future take flu epidemics seriously but something tells me that is unlikely. USA 2017-18, approx 80,000 died from flu and pneumonia. And yet they were not ready for anything this year.

  16. If you’re paying close attention, you may be noticing that the narrative, has, like our civilization, begun to fall apart.

    Expect, in the coming weeks, ever more strident CYA articles from people who simply cannot grasp that everything they’ve been saying is already in the hands of thepeople who are going to use it against them.

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