Hello,
The slow swell of new coronavirus cases that began shortly after Labor Day weekend resolved this week into an unmistakable third surge of the pandemic in the U.S., with more than 70,000 new cases reported on Friday the 16th, nearly tying the previous single-day records set in July. Hospitalizations are also rising sharply, and an increase in deaths is expected to follow. Meanwhile a clinical trial conducted by the WHO found that remdesivir and three other therapeutics that had been touted as potential breakthrough treatments had no measurable effect on Covid mortality. Only the steroid dexamethasone was shown to improve outcomes for patients who were severely afflicted. While a cluster of high-profile Covid patients seem to have recently made it through the disease without much incident thanks to early detection and advanced treatment, their experience won’t be shared by the vast majority of people who contract Covid over the coming months.
It is too early to know whether this new surge is the start of the big autumn wave some epidemiologists have been predicting with dread since the start of the pandemic (based on the historical pattern of flu pandemics), or instead the latest in a series of similarly-sized wavelets that will crop up periodically due to things like lockdown fatigue until a vaccine is widely administered (something like what the Imperial College London team envisioned early on under an adaptive suppression strategy, and also predicted as a possibility by the team at CIDRAP at the University of Minnesota).
But already this third surge is more wide-spread geographically than the first two, and wherever you are in the U.S., it probably makes sense to think about how you’ll make it through a potentially difficult two or three coming months safely and sanely.
Along these lines, one figure you might have seen bouncing around the internet lately is something called the “Swiss cheese” model of respiratory virus defense, which is helpful in one way and deeply unhelpful in another, and I’ll talk about both below.
The idea behind the Swiss cheese model (SCM from here on out) is simple enough, and more or less backed up by the science. When it comes to keeping yourself safe from SARS-CoV-2 no single prevention measure is foolproof. Each one has weaknesses, or holes, through which the virus can pass. You have to assume the virus will make it past one or more layers, and hope there won’t be enough holes in alignment to allow the virus to reach you. So for example it’s important to keep physical distance from people, but since aerosolized particles can linger and travel further than the recommended six feet of separation it’s important to also be outside or in a well-ventilated indoor setting. But even then, it’s important everyone wear a mask to reduce the amount of virus floating around in the air in the first place and to give at least some minor protection against breathing in the virons that do float in your direction.
The SCM is helpful because it pushes us out of our cultural bias to expect one-shot, on/off safety solutions. There’s a widespread suspicion of belt-and-suspenders approaches to safety that continually kneecaps the pandemic response in this country. It’s produced a string of failures that Ed Yong insightfully called the “serial monogamy of solutions.”
At the same time the SCM has some significant flaws that can lead you into danger, and they show up in the figure above if you look at it for more than the time it takes to scroll past it on Twitter. The problem is the order of the cheese slices. “Fast sensitive testing” and “contact tracing” show up as two of the final layers, a position in which they provide absolutely no protection. The point of these two interventions is to reduce the amount of virus in the social environment around you by identifying and isolating infectious people. If you’re already in a situation in which you need physical distance, ventilation, and a mask, it’s too late to test and trace — too late for you, anyway, though it might keep you from passing on the virus to someone else now that you’ve been infected. The other shortcoming of the diagram of course is that it ends on the right side with an individual, where we should be thinking in terms of transmission chains, where it’s just as important to keep people from passing a virus on to someone else as it is to stop them from getting it in the first place.
The SCM made its debut around the year 2000 as a general model for accident prevention. But its creator, James Reason, was drawing on the earlier work of sociologists Barry Turner and Charles Perrow, who introduced the ideas that disasters incubate over time and that they are expressed by cascading failures in big systems that in isolation are more or less harmless but that amplify one another in combination.
Reason’s SCM leaves behind some ideas from Turner and Perrow in a way that introduces some serious flaws into the model itself. In the SCM, there’s only limited interaction between the environment and the layers of protection, and the protective layers are visualized as independent and static — they don’t change, and failure in one doesn’t affect the others.
To see how this matters, think about Thanksgiving. For months, you’ve been wearing a mask, keeping distance from people, washing your hands, and staying outdoors. Perfect Swiss cheese defense, and you feel pretty comfortable and confident. Only now it’s late November, and you’re making the decision to go visit your family for Thanksgiving dinner.
In this scenario, as everyone arrives at the dinner, all kinds of interconnected problems crop up at once. First, the environment: the amount of community transmission of the virus will almost certainly be far higher in late November than it’s been since the late summer, so there are many more chances that at least one dinner attendee will have been exposed before arriving, relative to their chances of having been exposed before, say, a Labor Day BBQ, when there was far less virus in circulation.
It’s colder, too, so likely you’re carving the turkey indoors, with the windows closed, because who wants to eat a big holiday dinner swaddled in blankets and jackets. And since you’re around your family for maybe the first time in weeks or months, you’re probably inching closer to them than you otherwise might to a stranger, and taking your mask off a little more than usual to eat or to be heard over the din of everyone talking at once. And maybe you’ve got that one relative who thinks the pandemic is a hoax and hasn’t been masking or distancing, and isn’t doing it at the dinner. In any case, all the holes in the Swiss cheese have now come into alignment at once, and everyone’s vulnerable.
The CDC is worried that small household gatherings are increasingly driving the spread of Covid, and the holiday season provides the perfect set of circumstances for greatly speeding up that spread.
/ Swiss cheese and the federal response
Speaking of the CDC, ProPublica and Science both have must-read stories this week on the agency’s implosion over the course of the pandemic, unveiling a mixture of internal technical mistakes and weak leadership compounded by relentless political meddling from the White House that has led the CDC into “perhaps the darkest chapter in its 74 years, rivaled only by its involvement in the infamous Tuskegee experiment, in which federal doctors withheld medicine from poor Black men with syphilis, then tracked their descent into blindness, insanity and death.”
What does the CDC’s effectiveness and the wider federal response have to do with the SCM? They set the conditions for the effectiveness of everyone’s protection. Without a strong and coordinated national effort to drive down community transmission of the virus, more individualized protective layers like masks and distancing become less effective — there’s more virus to slip through the holes in the cheese.
// Quick Link Roundup
A legacy of racism in medicine…: A poll finds Black Americans are less likely to trust the medical establishment, in part because of the legacy of the Tuskegee experiments and because of the experience of everyday discrimination and exploitation in hospitals, doctors’ offices, and everyday life.
— “New Poll Shows Black Americans See A Racist Health Care System Setting the Stage for Pandemic’s Impact.” Michael A. Fletcher, The Undefeated.… drives distrust that complicates Covid vaccine trials: A deep-rooted skepticism of the motives of medical scientists is making recruitment of Black Americans into Covid vaccine trials difficult, a complicating factor for the development of a vaccine that will be safe and effective for everyone.
— “‘I Won’t Be Used as a Guinnea Pig for White People.’” Jan Hoffman, The New York Times.
— “Two Black University Leaders Urged Their Campuses to Join a Covid-19 Vaccine Trial. The Backlash Was Swift.” Nicholas St. Fleur, STAT News.“I used to call it the ‘scamdemic.’”: Take some time for this heartbreaking oral history interview with a 43-year old who thought the pandemic was overblown, and then watched it spread through generations of his family after a weekend gathering.
— “‘What are we so afraid of?’” As told to Eli Saslow by Tony Green, The Washington Post.“Totally Under Control”: Alex Gibney’s documentary about the pandemic is now available for streaming on demand. It’s beautifully crafted, and features moving interviews with some key players in the pandemic response. I’m not sure it reveals much that you wouldn’t know from having followed the news (or this newsletter in specific) over the last few months. It also pursues a pretty strident and sometimes overly simplistic argument (the pandemic is a matter of “politicians” vs “scientists,” and “nature” vs “society”). But it’s a good roundup of the missteps the U.S. has made in fighting the pandemic, and how we wound up in the terrible position we’re in now.
Taking a break from the pandemic: One of my favorite 55-minute stretches in this past week was this sublime reading by Edoardo Ballerini of Sam Anderson’s essay on the perils of perfectionism and the cracks weakening the ankles of Michelangelo’s David. Take a listen!
— “The Sunday Read: ‘David's Ankles’”. Produced by Sindhu Gnanasambandan; edited by Mike Benoist; written by Sam Anderson; and narrated by Edoaro Ballerini for The New York Times.
That’s it for this week, and I’ll leave you with one of my favorite scenes from Once Upon A Time in the West, where Henry Fonda sneers at a guy for wearing both a belt and suspenders — how can you trust a guy like that, he says, who can’t even trust his own pants? Anyway folks, Fonda’s character is the bad guy in this film. Wear your belt and suspenders, share the newsletter with a friend, and subscribe if you don’t already.