Calculating the risk of Thanksgiving dinner

Want to know the risk of being exposed to COVID-19 at your Thanksgiving dinner? In a paper released today by Nature Human Behaviour (part of the Nature family of prestigious journals), a team from Georgia Tech has created a handy-dandy online calculator that can do just that—as well as calculating the risk of being exposed at any other social gathering of any size, anywhere in the U.S. (and in some other countries).

Cutting edge science it is not: the math is basic probability. But it’s a cool website to play around with, and the announcement is very, very timely.

It’s primarily oriented toward policy-makers trying to decide what types of gatherings to allow, but it’s also revealing to any of us who are simply curious…and concerned about stemming the rapid spread of the virus.

Simply use the slider to pick the size of your event, then hover the cursor over your county, and it will tell you, based on current infection rates, the probability that at least one person is infected. (Note: it does not work on all browsers. Here’s the direct link in case you need to copy it to another browser. For me, it works on Firefox, but not Safari. https://covid19risk.biosci.gatech.edu/).

For example, it tells me that in Portland, Oregon, a gathering of 50 people has a 38 percent risk of having one or more infected people present. Ouch. Having ten people over for Thanksgiving isn’t as risky, but still carries a 9 percent chance.

And it’s a lot worse elsewhere. In my brother’s county in Iowa, a 50-person church service carries a stunning 97 percent chance of drawing an infected person, and that not-all-that big Thanksgiving dinner has a 50 percent chance.

There are some caveats.

  • The figures are based on the presumption that cases are under-reported by a factor of 10, something that is backed up by antibody tests in some parts of the country, but not others.
  • It assumes that everyone who tests positive is infectious. I don’t know if that’s true.
  • It does not tell you the chance that you yourself will become infected.

But if you’re looking for a reason to wear a mask, avoid large (or even mid-sized) indoor gatherings (and crowded outdoor ones), and to postpone major holiday celebrations, this is it. Me, I’ll celebrate Thanksgiving on my own, looking forward to next year, hoping to maximize the chances that my friends (and their loved ones) will still be alive to do it.

COVID-19 Becoming More Infectious, Study Says

Buried in today’s political news was a new COVID-19 study from Texas that found that the virus is becoming more contagious, and possibly increasingly able to circumvent control measures such as masks, hand-washing, and social distancing.

It’s really depressing news, though not really unexpected. What the researchers found was that 99.9 percent of recent cases in Houston appear to come from a previously uncommon strain of the virus—one that produces greater numbers of virus particles in their noses, mouths, and lungs.  That means that when they breath, talk, shout, cough or sneeze, they expel more virus particles, increasing the chance that someone nearby will receive an infectious dose.

The paper is posted on MedRxiv, an online site where scientists can post preliminary results while awaiting official publication. And while that means it isn’t peer reviewed, this doesn’t appear to be the type of research that can be easily messed up—especially if we don’t really care whether it’s 99.9 percent of new cases or 99 percent, or even 90 percent.

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When 6 Feet Apart Is and Isn’t Enough

One of the standard pieces of advice for people trying to prevent the spread of COVID-19 is that we need to either stay 6 feet apart or wear masks. But does anyone really believe the danger zone is that sharply defined? Especially because study after study has shown that exhaled droplets, especially small, can travel larger distances than once thought.

At the same time, we know that ventilation matters, because it markedly affects the number of virus particles you might inhale if you are unfortunate enough to be exposed.

A new paper in BMJ (formerly the British Medical Journal) has addressed that topic in unusual detail, producing a very thorough (and easily read) graphic detailing the relative risk in a wide range of situations.

The result is good news for outdoor enthusiasts (such as runners, cyclists, and hikers), mixed news for outdoor gatherings, and bad news for bars and restaurants.

Nothing surprising there, but the graphic is cool, and useful.

Here’s the link to the study, in case the image above isn’t readable on your device. The image is a few pages down.

Super-spreaders, COVID-19, and the rural/urban divide

Nobody wants to be in a state with a lot of COVID-19 cases. Nobody except perhaps an epidemiologist trying to study how the disease spreads.

In a paper in today’s Proceedings of the National Academy of Sciences, a team from Emory University (in Atlanta) and the Georgia Department of Public Health, took advantage of the fact that their state ranks 6th in the U.S. in per capita cases to hone in on just how the disease spreads.

They looked at data from the five counties in the state with the most cases, looking for, among other things, superspreader events.

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What the Georgia summer-camp outbreak tells us about COVID-19 & Schools

Today’s COVID-19 news contained the depressing information that 260 of 597 attendees at a Georgia summer camp had tested positive to COVID-19. As super-spreader events to, that was a whopper. It also bodes poorly for opening schools in the fall. (Image credit: Taliroll / CC BY-SA, creative commons license.)

But with everything else in the news today, details were slim. And even the best news sources can mess things up. So I went to the CDC journal article on which it was based. You can find it here. These reports are a bit dry, but generally readable, and this one was no exception.

Her are the basic facts:

Continue reading What the Georgia summer-camp outbreak tells us about COVID-19 & Schools

Why a Mask IS a Political Statement…Just Not a Partisan One

Unless you’ve had the news turned off for the past week, you know that the Mask Wars are on, with a lot of people suggesting that wearing a mask marks you as a Democrat while not wearing one marks you as Republican.

And superficially, there’s something to that. We have a President who declines to wear a mask in public and who not only taunts Joe Biden for wearing one, but at a recent press conference shamed a reporter for being “politically correct” when the reporter refused to take off his mask at the President’s request.

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Covid-19 & the Emperor’s New Clothes

We all know the story of the emperor’s new clothes. In it, the emperor is hoodwinked by rogues who take his money and make him…nothing. “Nothing” that his advisors, fearful of offending him, declare to be the finest finery in the land.

Then, the emperor dons the non-existent robes…and a little child calls him out, exclaiming, “But the Emperor has nothing on at all!”

Except…The original fable, by Hans Christian Andersen, is a little more complex.

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How to Make COVID-19 Evolve to Become Less Dangerous

Donald Trump says that even without a vaccine, COVID-19 will eventually fade away. And amazingly, the science says he might be right…though not if we follow his plan for reopening the country.

The science in question is evolutionary virology.

It says is that under certain circumstances viruses will evolve into less virulent forms. In fact, this might even be what happened to the 1918 Spanish Flu…though not until after it killed tens of millions of people.

Let me explain.

In order to be an evolutionarily successful, virus can’t just infect one person, they have to jump from one person to another. They can do that by making us cough, giving us diarrhea that contaminates other people’s food or water, or giving us sores that shed virus particles onto anyone or anyone we touch.

I.e., they make us sick.

But if they make us too ill, too quickly, they don’t get much chance to spread because we either collapse into bed, away from other people, or make others leery enough of catching the disease that they take suitable precautions.

Continue reading How to Make COVID-19 Evolve to Become Less Dangerous

The Corruption of Critical Thinking

This post is not directly about politics or COVID-19. But it should be, which is why I’ve tagged it for both.

When I was teaching at California State University, Sacramento in the late 1980s, the Cal State system was trying to increase the focus on classes that emphasized critical thinking.

If there was an official definition, I never saw it, but my department made it clear that the environmental studies law-and-public-policy classes I taught were exactly what they wanted.

I ran these classes not as lectures, but as discussions based on assigned readings, and my biggest goal was to challenge the students to think about the readings’ implications, rather than just taking them at face value.

One of my favorite moments was a discussion in which one of the students flipped whatever I was saying at the time back on itself and pointed out something I’d overlooked. “That’s what you taught us to do,” he said, when he realized how well he’d hoisted me by my own petard.

I don’t remember what grade he got for the course, but for that day, he definitely got an A+.

Since then, however, I’ve found that critical thinking is all too often replaced by shorthand substitutes.

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Scylla, Charybdis & COVID-19

In Greek mythology, Scylla and Charybdis were monsters guarding opposite sides of the narrow strait between Italy and Sicily. Chart a course too close to one side, and Scylla grabs you. Try to steer clear of Scylla and you fall prey to Charybdis.

It’s hard to think of a better metaphor for the modern moment.

Except…in the Greek lore, the two monsters acted independently. Now, it’s more like each isn’t so much trying to snare you for itself as to drive you into the other’s clutches. And it’s something we seem to be doing our level best to assist.

Let me elaborate.

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