Skip to Main Content

Back in April, President Trump picked out a single computer model of coronavirus spread as his oracle of choice. Unsurprisingly, that simulation initially had rosier estimates than other algorithms, projecting many fewer Covid-19 deaths — and its unconventional calculations and fluctuating estimates drew sharp criticism from epidemiologists.

But the statisticians behind it have since changed their methods, and their new numbers, published Friday, bolster what scientists have long been saying: That doing away with social distancing measures could entail vast numbers of deaths, and that widespread mask-wearing in public could save tens of thousands of lives.


“We think the key point here is that there’s a huge winter surge coming,” Christopher Murray, a lead author on the paper and the director of the University of Washington’s Institute for Health Metrics and Evaluation, said in a press briefing. At this point, the wave isn’t fully preventable, but “expanding mask use is one of the easy wins for the United States.”

Specifically, the paper projected that there could be some half a million Covid-19-related deaths in the U.S. by the end of February, and that some 130,000 of those tragedies might be forestalled with universal mask use. But experts warn that the figures from any of the model’s hypothetical scenarios are less useful than the comparison between the different possibilities. By putting those projections side by side, you can start to see how much of an effect something like mask-wearing might have on a population level, if you take the authors’ estimation that face coverings can reduce an individual’s risk of infection by about 40%.

“The exact numbers are impossible to predict,” said Ruth Etzioni, a biostatistician at the Fred Hutchinson Cancer Research Center and the University of Washington, who was not involved in the new research. “What should drive policy here is the difference between the scenarios with and without masks.”


The IHME team’s initial work last spring didn’t try to model transmission rates and incubation periods of the novel coronavirus, but rather tried to fit the United States onto data from outbreaks elsewhere, and showed a bell-like curve, with cases largely rising and falling symmetrically. Their projections also wobbled a fair amount, and as Nicholas Reich, a University of Massachusetts, Amherst, biostatistician whose team compares a number of different Covid-19 models, described them to STAT, “were inaccurate and did not reflect the consensus of the modeling community.”

The IHME then switched to a more traditional way of modeling infectious disease, which aims to calculate the mathematical cascade of transmission: the number of people susceptible to the disease, how many of them get exposed, how many then get infected, and how many recover and therefore have at least temporary immunity.

Once the institute made the switch, Reich explained, “their more recent short-term forecasts, which have been submitted to the COVID-19 Forecast Hub, have performed reasonably well in accuracy for up to one month into the future. They aren’t the best model, but they seem to be making reasonably accurate short-term predictions.”

This paper, however, extends beyond that one-month mark, and the further you go into the future, the greater the uncertainty of projections. The team used state-by-state data from the past on case rates and all sorts of other variables—such as cell phone mobility data, seasonal pneumonia fluctuations, levels of mask use—to then project how tweaking those variables might shift the results.

This sort of analysis is not designed to tell us how effective wearing a mask is at reducing disease spread. Rather, that is just one of many bits of information that the researchers fed into their model — and their estimate on that front comes from a meta-analysis they did of previous peer-reviewed studies and preprints that looked specifically at that question.

Nor should we expect this model to give any sort of certainty about what the future holds.

“It’s not a forecast per se, because the outcomes are conditional on very specific model assumptions about how effective masks are and how much uptake there is in wearing masks,” Reich said.

Instead, as Zeynep Tufekci put it in The Atlantic, we should use this sort of study for “pruning catastrophic branches of a tree of possibilities that lies before us.”

Because all sorts of policy and behavior changes took place at once, it’s nearly impossible to pick apart the influence of any one strand. What this sort of analysis can provide is a hint of the general direction we should be headed — and the ones we should avoid — to keep as many people as possible safe. Given that a scenario in which every single person wears a mask in public all the time results in many fewer deaths than one in which mask use continues at its estimated current pace, one effective course of action seems pretty clear, the authors say.

As unsurprising as their conclusion is, it can still be useful to say it.

“We don’t need a model to tell us that we should all be wearing masks, we don’t need a model to tell us that if we continue the way we’re going, we’re going to see tens of thousands more deaths within the next couple of months,” said Etzioni. “But sometimes when a person provides a model and you see these curves and you see these numbers, it helps appropriately freak you out.”

She added that it might also help bolster public health policy decisions: “A model like this can be very important for our governors who are actually trying to do something to enforce mask mandates. They’re not popular, so politically it can make it tough on a governor who’s trying to do the right thing. Models like this can provide a kind of evidence to support that policy.”

  • STAT has not addressed the Great Barrington Declaration nor the related success that Sweden has had in dealing with the virus. Given the wildly wrong models that began the panic, it is astonishing that STAT is still looking to them for direction.

  • Universal mask wearing will not solve the problem unless people are wearing the right mask and wearing it properly. This will prevent infected people from discharging the virus onto the air in public places.

    The problem:

    1. people wearing the mask under their nose
    2. people wearing their mask covering only the tip of their nose enabling the virus to enter the public air.
    3. people wearing mask with materials that allow virus to escape thru space between weave in the mask.
    4. Dog / cats snipping the ground and end up getting covid.
    5. People removing and putting the mask back improperly which can cause the inside of the mask to be contaminated.
    6. improper handling of contaminated mask, cloths, items etc.

    The list can go on. People need proper eduction on how to wear mask and how to protect themselves from this COV-SAR2.

    Then virus can survived longer in it infectious form with winter approaching. It will become like flu and cold and will stay will us forever since it infect different species of animals. What we needs a long term plan and knowledge on how to protect ourselves.

  • Since the Democrats resolved to battle with Trump on the only thing that they could, they and the media decided to broadcast worse case news 24/7.
    This was a conscious decision.
    Since it has been politicized, it is difficult to extract real, factual information on the results of infection, death rates, recovery rates and the physical, mental and financial effects of economic closures.
    Such a shame.

  • 1) Universal mask wearing is not legally nor practically possible.
    2) Universal mask wearing would not stop the spread as many suggest.
    3) Already, those who wear masks will continue and those who oppose will not.
    4) Soon ant-viral drugs and vaccines will mitigate this extraordinary mandate.
    5) This is a worldwide pandemic of a new, novel, fast spreading virus and earthlings will have to decide on their own level of mitigation until the virus can be fully eliminated. Universal mandates are more unfair and harmful than the illness for a majority of the people.

  • OK. But what I don’t understand is why, despite increasingly huge numbers of people wearing masks, the virus continues to infect growing numbers of people. We are wearing masks. Not universally. But we are using the heck out of them. And still the virus infection expands. If masks were working, the incidence should be decreasing. But it’s not.

  • And “the team used state-by-state data from the past on case rates…” So it’s all built on faulty data to begin with, seeing as numbers of cases aren’t even close to being correct.

  • According to the official CDC data around 85% of those infected with COVID-19 have worn masks always or most of the time, but only 4% never wore masks. This means wearing a mask increases the probability of an infection more than 20 times. Overwhelming evidence shows that masks will multiply infections, not reduce them.
    The government is not your friend. All COVID-19 measures and restrictions have the sole purpose to make you sick, not to protect you (e.g. depriving you of Vit. D, increasing stress levels, withholding effective treatments etc.). They want to increase infection numbers in order to justify their lockdowns, they do not to reduce them. Think and don’t be fooled!

    • That’s not how math works broh.

      Look, if you don’t want to wear a mask because you don’t care enough about the health of others to do this small thing, just own it and say so. But don’t pretend your behavior can be justified with numbers and reason, you’re embarrassing yourself.

  • Once again, the crude modelers at IHME are pontificating about things in the future they can’t really EVER know and thus can’t really predict.

    However, Eric, despite your assertive headline about mask use–which if folks were just skimming they might conclude, “well, that’s settle,”– it is very commendable of you to mention Tufekci’s piece from The Atlantic.

    As Tufekci points out, SEIR modeling is unrealistic. This virus doesn’t operate randomly in the population the way, say, height is randomly distributed. The little bugger moves around in a lumpy stochastic fashion, not a deterministic one.

    As such, the vast majority of mask wearing likely has ZERO effect and ZERO benefit. Same with social distancing. It’s theater. When you see people in the park or in their own car with masks on, they’ve become unwitting actors in a ludicrous farce.

    Now if you could pinpoint the rabid spreaders — the likely very small set of folks to who are responsible for the vast majority of transmissions and have THEM wear masks and hide in their basements — well, then you would be getting somewhere. But ain’t gonna happen.

    So Eric, you write:

    “What this sort of analysis can provide is a hint of the general direction we should be headed — and the ones we should avoid — to keep as many people as possible safe.”

    A very articulate expression of the new “ism” — safety-ism. But like most “isms” safety-ism has costs. And the negative tradeoff between the costs and the benefits of “safety” is becoming starker as the covid lockdown persists: crushed livelihoods, rampant depression, excess deaths from OTHER syndromes and diseases where treatment was put on hold because of panic about this virus.

    Finally, it is becoming clear that epidemiology is a very weak scientific discipline, if we can call it a science at all. There isn’t, and likely never will be, falsifiable hypothesis testing in the discipline. The IHME guys, the yahoos at the WHO, the CDC mafia, Fauci — they stick their index fingers up in the air, feel the way the wind is blowing, and then trot up to the podium and with studied gravitas to tell us one thing, and then another, and then something obviously ludicrous, and journalists run to their computers and breathlessly report.

    You know what the major benefit will be when this is all over? We won’t have to hear anymore from these pompous PhDs.

    • Gene, maybe…but that assumes you CAN have everyone wear a mask at all the right times, and correctly. It also assumes that every mask in 100% effective given the tiny size of the virus particle, and given its ability to remain in the air or on surfaces. If everyone was wearing a N95 and face shield, then it MIGHT be possible.

      But we have the false assumption that if everyone wears a mask we will bring this virus to screeching halt. Unlikely.

      And even in places where mask wearing was mandatory, the virus spread. The sum of what we still don’t know still vastly exceeds what we do.

      Again, it’s theater.

    • Actually, if we can get widespread testing and contact tracing done, we could graduate into a mostly mask-free society. But sure, if you want to play Russian roulette with other people’s lives and health, repudiating masks is one way to go… to exponentially higher mortality rates.

    • Sshh, just stop thinking because you have a bunch of letters after your name and kissed the feet of Fauci that you know better than everyone else.

      You don’t.

      Epidemiology consists of post-hoc “natural” experiments presented to them by events over which the “scientists” have little if any control. It is not true science. You can’t predict — you can’t EVER prove — that masks are somehow a panacea that same way Einstein predicted that the starlight would be bent by 1.7 arc seconds due to the curvature of the sun’s space-time grid.

      C’mon, can you tell us now what the Covid infection fatality rate is? Will you be able to tell us EXACTLY what it will be? After this is all over, maybe you’ll be able to come up with a reasonable approximation, but even then you won’t REALLY know. It will be a guess.

      How many of the “cases” are in fact false positives? How many of the tests are “false negatives?” The going number for fatalities in 220,000 — how many of them are directly causally related to the virus? And how many are simply cases where confounding co-morbidity variables predominated? Do you know? Does anyone REALLY know?

      We had a public health official in Chicago say they were going to count as a Covid death anybody who HAD Covid when they died. In Florida, they had a victim of motorcycle accident counted as a Covid death because they were positive. I have very good friends who live Belgium who have informed me that virtually every nursing home death was attributed to the virus.

      And this is science?

      Birx said back in March if deaths stayed around 200,000, we would have done things perfectly. We’re at 220K as of this writing. Have we been almost perfect then? Suppose we get to 300,000. How is THAT performance? What’s our grade then? Did we do things correctly two thirds of the way? Is this number directly causally attributable to things we did? Or didn’t do? Can you prove it?

      You can’t.

      And what about the cost of tradeoffs? What are those? Are they worse relative to the benefits of “fighting” the virus? My guess is that the costs will far outweigh the benefits. But I’ll admit it’s a guess. Fauci will never admit he’s guessing.

      Speaking of Fauci, there is one thing he is very skilled at–gravitas laden pontifications. First he says we shouldn’t be too worried, and then it’s panic time. He says masks probably don’t work, and now we HAVE to have masks. We shouldn’t shake hands EVER again, but having anonymous sex with a person you meet via an dating app is just fine.

      See, here’s the bottom line problem. Our “science” betters, and maybe you among them Dr. White, have ZERO, and I mean ZERO humility. Nada. Zilch.

      There’s this REAL scientist, you may have heard of him. His name was Richard Feynman. Here is what he said about science.

      “What is science? Science is the belief in the ignorance of experts.”

    • Erich, just so you know, I’m fine with mask wearing. I wear one in my locale. It’s annoying, and I don’t think it makes a real difference but I’ll play along.

      I don’t object to the wearing of masks — what I find appalling is that the IHME modelers diddle at their computers and come out with some SEIR based number with the authority of cake frosting that masks will “save 130,000 lives.”

      They can’t possibly know that, and they can’t possibly set up an experiment that will test that hypothesis, or even create a post hoc analysis that will confirm that hypothesis. It’s equivalent to soothsaying, cloaked in the klunky prose of a scientific article.

      And then we have Redfield of the CDC, an equally blowhard pontificator saying in front of Congress — in public!! — that masks may be more effective at protecting against COVID-19 than a vaccine.

      Good grief.

      These are our public health officials. It’s a wonder we have ANY public health with these clowns in charge.

Comments are closed.