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Many of the largest outbreaks of SARS-CoV-2 in the USA so far have been in certain kinds of workplaces, including nursing homes and prisons, both of which make sense. But there are also many outbreaks in *meatpacking* plants. Why this occupational venue? Let’s talk about this. 1/
In a list of outbreaks via @nytimes (…), other than nursing homes and prisons (and two ships), meatpacking plants are most frequent locus of outbreaks (7 out of top 30 outbreaks). The largest outbreak outside of a prison is in a *meatpacking* plant. Why? 2/
The Smithfield meatpacking facility in Sioux Falls, SD, had the largest non-prison COVID19 outbreak in USA, with 1,095 cases as of May 1. The first person to die was 64-year-old Augustin Rodriquez, who worked in the pork-cutting department:… 3/
Sometimes, in face of an outbreak, companies implement foolish policies (from a public health perspective), such as paying workers more to show up. Smithfield offered a $500 “responsibility bonus” for workers who did not miss a shift for all of April.… 4/
But this contributes to spread of the epidemic! A better approach would be to pay workers more on a daily basis (so that they like their jobs more & so that the plant can recruit more workers) while also increasing & liberalizing sick leave, so more (sick) workers stay home. 5/
Of course, careful attention to working conditions in meatpacking plants also is crucial. 6/
The frequency of COVID19 outbreaks at meatpacking plants has gotten so extreme that there has apparently been concern that the nation’s food supply would be affected (…). 7/
On the White House website on April 28, the president said he intended to invoke the Defense Production Act (ordinarily intended for wartime emergencies… ) to force meat companies to stay open.… 8/
The president declared that meatpacking plants were part of the nation’s “critical infrastructure” given that “closure of any of these plants could disrupt our food supply and detrimentally impact our hard-working farmers and ranchers.” 9/
No mention was made of detrimental impact on hardworking *meatpackers* facing the COVID outbreaks, however. And why meatpacking factories would be ordered open but not PPE factories (to help hospital personnel and patients) is also a bit odd to this public health professor. 10/
But why might meatpacking factories have COVID19 outbreaks in particular, compared to other industrial settings? 11/
Meatpacking is dangerous, has cuts, bruises, and abrasions. “Very turbulent air conditions” often prevail, and steam can be present too. One old observational study concluded that workers have higher cancer risk, possibly from contact w animal viruses.… 12/
Here are two videos available online (in exceptionally sanitary conditions, but you can see the kind of work involved) that show the work situation: and (beginning at 4’20”): 13/
Does meatpacking involve the creation of aerosols and has this possibly caused occupational respiratory outbreaks before? Yes, it has. For instance in this classic 1962 study:… 14/
And here is another outbreak (possibly connected to aerosols) of Legionnaire’s pneumonia in an Austin, MN meatpacking plant in 1957, as retrospectively analyzed in 1983:… 15/
In the 2003 SARS-1 outbreak, several super-spreading events were associated with the aerosolization of contaminated body fluids, including possibly vomit at the Metropole Hotel and diarrhea at the Amoy Gardens Estates (, both in Hong Kong. 16/
There is also concern, in the setting of the 2020 SARS-CoV-2 pandemic, of the possible aersolization of virus from patient secretions in ICU settings, via faulty ventilators or nebulizers, with consequent spread to health care workers.… 17/
So that is my theory: meatpacking industry involves a combination of close worker proximity and the intrinsic production of mist and aerosols (eg, through the use of saws) such that any infected worker who coughs will have his expectorated virus wafted to others in the plant. 18/
It turns out that meatpacking plants in many other countries are hard hit by COVID19 too:

Brazil:… via @Nuno_tuga_ @ckieling @trasel

Australia:… via @AblokeimetAus

Spain:… via @malfeiner

Still more countries w curious phenomenon of COVID19 outbreaks in meatpacking plants:

Ireland:… via @ellamcsweeney @Campaignfornia1

Portugal:… via @joaomiranda

Canada: via @CarmelApicella @VinasJose

And there are still other countries with the curious phenomenon of meatpacking plants hard hit by COVID19:

Germany:… via @West_Looper

And Israel and several other countries. 21/
Of course, meatpacking plants have been notoriously bad places to work, powerfully shown by Upton Sinclair, in his novel, The Jungle, describing the lives if immigrants toiling in the Chicago meatpacking industry in the early 20th century:… 22/
Many COVID19 outbreaks in meatpacking plants involve immigrant workers!

In USA: Mexicans… (old story)

In Canada: Filipinos…

In Germany: Romanians…

This wrongly contributes to anti-immigrant sentiment.

In addition to worker proximity, intrinsic production of mist & aerosols (eg, through use of saws), & policies discouraging sick leave, meatpacking is in a chilled environment. All may facilitate spread of SARS-CoV-2. Many occupational situational factors are surely involved. 24/
It turns out there is even a recent wikipedia page on this phenomenon:…

And @jonkay featured many meatpacking outbreaks in his fine catalogue of super spreader events… 25/
For more details on how the meatpacking industry works and the (albeit unclear how distinctive) difficulties in coping with COVID19, see this long and informative thread, via @rudman_ben: 26/
Report re meatpacking COVID19 outbreaks via @CDCgov is just out… In 115 facilities in 19 states w ~130,000 workers, there were 4,913 cases (3%) & 20 deaths (CFR=0.4%, so far). Report highlights worker proximity & crowded living/transportation. 27/
What @SecAzar @HHSGov has to explain, though, is why workers in meatpacking factories all over USA & indeed worldwide are affected, and also why other industries are not. No, I think there's something to meatpacking per se. Let's do some epidemiology.… 28/
More reporting and ideas here via @MeganMolteni @WIRED on COVID19 risk in meatpacking industry.… 29/
Unsurprisingly, if you allow (let alone encourage) an unchecked epidemic in a location (like meatpacking plants), it spreads to the surrounding community. That's what epidemics do. (Usual causal inference caveats apply.) via @MikeDorning @business… 30/
Analysis of "6-feet rule” in turbulent air conditions (which is relevant to meatpacking and other outbreaks):
based upon extensive simulations of coughing & airborne droplet transmission, saliva droplets can travel 18 feet in light wind.… via @EricTopol 31/
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