Public Health Logic vs. #MasksForAll

Public Health Logic vs. #MasksForAll April 2, 2020

I’m not an epidemiologist, but I do sometimes teach logic.  So check out this bit of public health polemic from CIDRAP:

There is some evidence that surgical masks can be effective at reducing overall particle emission from patients who have multidrug-resistant tuberculosis,36 cystic fibrosis,34 and influenza.33 The latter found surgical masks decreased emission of large particles (larger than 5 µm) by 25-fold and small particles by threefold from flu-infected patients.33 Sung37 found a 43% reduction in respiratory viral infections in stem-cell patients when everyone, including patients, visitors, and healthcare workers, wore surgical masks.

In sum, wearing surgical masks in households appears to have very little impact on transmission of respiratory disease.

I suppose it all depends on what your definition of “very little” is.  43% reduction in viral respiratory infections?  Sure, I’d like a little of that.

If there were an anti-viral pill that cut infection rates by 25% or 30% or 45%, with virtually no side effects, no drug interactions, available in generic at minimal cost . . . you’d be taking it every day.  They’d probably put it in the drinking water.

If it were a shot and you refused to give it to your newborn, you’d receive stern warnings and a note in your chart that you’d gone AMA.  If you persisted in your refusal, your children would be banned from public schools.


That’s surgical masks, of course, which are in short supply and therefore logic tells us they should be saved for the situations where they are needed most.  Your homemade cloth mask is less effective.  And yet, weirdly, I’ve never been to a doctor’s office where the flu-prevention poster says Covering your cough does nothing.  Don’t bother.

Who are these physicians who would like to come to my house right now, as I’m sitting here recovering from a wicked sore throat and intermittent aches and a nasty headache yesterday, all of it well above-and-beyond even this year’s steady allergies, but those allergies are still making my nose run something amusing . . . who are these doctors who want to come sit with me while I sneeze on them and chat at them and would seriously say, “No, don’t bother covering your face, it doesn’t do anything.”

But if it’s a Walmart employee, then that’s okay?

I think not.


Let’s say that widespread use of homemade and improvised masks only cuts the spread of COVID-19 by 10%.

Is there an ER doctor out there who doesn’t want to cut caseload by 10%?  Is there an ICU nurse thinking, “Nah, 10% few patients?  Why would I care about that?”

If our politicians invested a billion dollars in a spending program that cut spread of the disease by 10%, they’d be touting it election cycle after election cycle for the remainder of their career.  But if it can be accomplished for free using materials you have sitting around your house?

Never mind.  Not worth it.


There is some evidence that piling on the “not very effective” public health measures can save lives. Here’s a discussion of preliminary evidence that lowering the amount of virus one is exposed to can reduce severity of the disease.

Here’s a discussion for the lay audience on the challenge of transmission among asymptomatic and minimally-symptomatic persons, which is more of a thing for COVID-19 than for other viruses.

Use your logic skills: If washing hands helps a little, and covering your cough helps a little, and keeping six feet away helps a little . . . then all three combined helps a little more.  Yes?  Yes.

Y’all.  Have mercy on the doctors and nurses who are dying from exposure to this virus.

Stay home when you reasonably can.

Wash your hands.

Use physical distancing, barriers, minimal contact, and disinfecting to make work life safer.

Favor outdoor over indoor meeting locations.

Cover your mouth and nose.

And I’m gonna say it now, even though I’m not hearing it yet: Put on whatever glasses you have on hand and thereby reduce the number of droplets hitting your eyes.

While we’re at it . . . Eat as nutritiously as you can, get exercise, and generally take care of yourself.

Slow. it. down.

File:English language poster on good habits to prevent influenza.pdf

Artwork: A poster explaining that covering your face when you cough or sneeze is helpful.  (Wikimedia, Public Domain). But apparently the droplets of moisture that come out of your mouth and nose when you talk or breathe can be spewed freely and that’s fine?  Or is covering your cough just a big fat lie?  I think not.  Every little bit helps.

Cover it up . . . slow it down.

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