"Identifying transmission events is more important than identifying infected individuals."

[Dark n Stormy Knight]

This, from the Atlantic, was posted recently here on DU at least once (by Roland99), but didn't get much attention. It seems to be a super important article on how COVID-19 spreads. I hope more here will read it. Not least because discussion here might help me figure out if I'm correctly understanding what the piece is saying.

This Overlooked Variable Is the Key to the Pandemic
It’s not R.

There’s something strange about this coronavirus pandemic. Even after months of extensive research by the global scientific community, many questions remain open.

Why, for instance, was there such an enormous death toll in northern Italy, but not the rest of the country? Just three contiguous regions in northern Italy have 25,000 of the country’s nearly 36,000 total deaths; just one region, Lombardy, has about 17,000 deaths. Almost all of these were concentrated in the first few months of the outbreak.

What happened in Guayaquil, Ecuador, in April, when so many died so quickly that bodies were abandoned in the sidewalks and streets?* Why, in the spring of 2020, did so few cities account for a substantial portion of global deaths, while many others with similar density, weather, age distribution, and travel patterns were spared?

What can we really learn from Sweden, hailed as a great success by some because of its low case counts and deaths as the rest of Europe experiences a second wave, and as a big failure by others because it did not lock down and suffered excessive death rates earlier in the pandemic? Why did widespread predictions of catastrophe in Japan not bear out? The baffling examples go on.

The now-famed R0 (pronounced as “r-naught”) is an average measure of a pathogen’s contagiousness, or the mean number of susceptible people expected to become infected after being exposed to a person with the disease. If one ill person infects three others on average, the R0 is three. This parameter has been widely touted as a key factor in understanding how the pandemic operates.

Unfortunately, averages aren’t always useful for understanding the distribution of a phenomenon, especially if it has widely varying behavior. If Amazon’s CEO, Jeff Bezos, walks into a bar with 100 regular people in it, the average wealth in that bar suddenly exceeds $1 billion. If I also walk into that bar, not much will change.

Clearly, the average is not that useful a number to understand the distribution of wealth in that bar, or how to change it. Sometimes, the mean is not the message. Meanwhile, if the bar has a person infected with COVID-19, and if it is also poorly ventilated and loud, causing people to speak loudly at close range, almost everyone in the room could potentially be infected—a pattern that’s been observed many times since the pandemic begin, and that is similarly not captured by R. That’s where the dispersion comes in.

There are COVID-19 incidents in which a single person likely infected 80 percent or more of the people in the room in just a few hours. But, at other times, COVID-19 can be surprisingly much less contagious. Overdispersion and super-spreading of this virus are found in research across the globe.

A growing number of studies estimate that a majority of infected people may not infect a single other person. A recent paper found that in Hong Kong, which had extensive testing and contact tracing, about 19 percent of cases were responsible for 80 percent of transmission, while 69 percent of cases did not infect another person.

This finding is not rare: Multiple studies from the beginning have suggested that as few as 10 to 20 percent of infected people may be responsible for as much as 80 to 90 percent of transmission, and that many people barely transmit it.

It's long, but seems to present key info best understood by as many of us as possible. Please check it out, here, it if you can. (Maybe bookmark it for later, if now isn't a good time.)

[Roland99]

1. ....

[Mme. Defarge]

2. A very interesting article.

[Phoenix61]

3. Very interesting. I'm curious when Japan

instituted wide-spread mask wearing.

[Dark n Stormy Knight]

4. I assume you mean after COIVD-19 was discovered?

It does seem that the citizens of Asian countries have been more willing to wear masks to stop the spread of infectious disease than most of us, well before this new plague. But as to your question, I don't have an answer.

[Phoenix61]

5. I was in contact with someone living in

Singapore when the virus first hit there. He said they had learned a lot from SARS. And yes, they are more willing to wear a mask. Of course they don’t have whack jobs turning a public health behavior into a political statement.

[Dark n Stormy Knight]

6. "Of course they don't have whack jobs turning a public health behavior into a political statement"

That seems to really help, in so many ways!