Uncovering COVID-19’s Most Risky Activities

I don’t have time to digest this in detail today, but this is important. It’s condensed from a press release from Nature (slightly edited to condense it):

“Reopening places such as restaurants, fitness centers, cafes, and hotels carries the highest risk for transmitting SARS-CoV-2, according to a modelling study based on data from the United States published in Nature. Reducing occupancy in these venues may result in a large reduction in predicted infections, the model suggests.

“Jure Leskovec and colleagues use[d] US mobile phone data (collected between 1 March and 2 May 2020) to map the movements of millions of people from different local neighbourhoods. They combine[d] these data with a model of SARS-CoV-2 transmission, which allow[ed] them to identify potential high-risk venues and at-risk populations.

“The level of detail of the mobility data allowed the researchers to model the number of infections occurring, by the hour, at nearly 553,000 distinct locations grouped into 20 categories — termed ‘points of interest’ — that people tended to visit regularly. Their model predicts that a small number of these locations, such as full-service restaurants, account for a large majority of infections. For example, in the Chicago metropolitan area, 10% of the points of interest accounted for 85% of the predicted infections at points of interest.”

That’s a bit technical, but it says what we all need to realize: certain activities are higher risk, and high-risk activities account for the vast majority of the virus’s spread.

Today, this also would, most likely, include Thanksgiving festivities.

We have a vaccine on the cusp of becoming available. Patience will save lives. Be patient. Hold the course. The end may be in sight.

One caveat re the study: it’s data are from the first wave of the pandemic, in March and April. Some of the “points of interest” may subsequently have learned how to reduce the risk. But the main idea still applies: the vast majority of the spread comes from a small fraction of sources.

This finding is particularly interesting: “[C]apping the occupancy of a venue at 20% of its maximum capacity is predicted to reduce new infections by over 80%, but would only reduce the overall number of visits by 42%.”

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.

Masks: the Golden Rule is not a sign of weakness.

I’ve said this before (in fact, I’m using the same photo as last time), but it’s worth repeating. The latest run of the University of Washington’s coronavirus model shows 363,000 deaths by the end of December, with the death rate hitting 2,900 a day by then–a horrible projection for what might happen in January.

But if we can raise the rate of mask-wearing, especially indoors, that number of deaths falls by 86,000. Given that more than 200,000 people have already died, that means the number of new deaths is cut in half. Simply by biting the bullet and wearing masks. (Note, I may not have these figures exactly correct; this was breaking news on TV a few minutes ago, and I didn’t have time to grab a pen. But I’m close enough.)

Mask wearing is not a sign of weakness. It’s not even something you do for yourself. It protects you some, but it works best if the people around you are also doing it.

Mask wearing is something you do primarily for others.

If they reciprocate, THAT protects you. But even if they don’t, it sends a signal of strength. “I care.” Why is that so controversial?

It’s the Golden Rule in action.

It’s that simple.

My 2016 Book…and the London Marathon

Back in 2016, I coauthored a short book (more a novella than a novel) with Phil Maffetone about a hypothetical “Million Dollar Marathon,” in which runners competed on a one-mile track, with the giant prize to anyone who could break 2 hours.

It’s fiction—I thought of it as near-future science fiction, since that is part of what I write—focused on a Tibetan refugee whose background gives him all the tools needed to make this quest possible.

Now, this weekend, the London Marathon—thanks to COVID-19—will be conducted under a protocol amazingly similar to that in our book. The best in the world, male and female will duel on ~20 laps of a 1.34-mile loop.  Not a track, but not all that different from Phil’s and my setup.

Continue reading My 2016 Book…and the London Marathon

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.

Continue reading COVID-19 Becoming More Infectious, Study Says

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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