Coronavirus Chronicles — Beware the Delta, Continued

Earlier this month, at, complex systems researcher Carlos Gershenson noted that in the United States, COVID-19 cases and deaths were at their lowest point in a year, and went on to argue convincingly that it was too early to relax:

With more than half of the population vaccinated, it may seem that the worst has already passed. As we observe what is happening in other countries, however, we believe it is too early to relax. The U.K., Chile, Uruguay, Bahrain, and Mongolia have vaccinated more than half of their populations, but their COVID-19 cases are increasing.

In the previous post, we mentioned that the Delta variant of COVID takes root in people’s air passages more readily than its predecessors, and this probably makes it easier to transmit to others. Over the past months, the public has been warned to limit contact with anyone who has the virus, or might have it, to five consecutive minutes or 15 cumulative minutes.

In reality, we don’t know all the rules about how transmission works, partly because contact tracing has never really been a big feature of the American anti-virus strategy. Last year, it was only a rare combination of circumstances that allowed authorities to understand how one man’s visit to Tucson, followed by attendance at church, brought the pandemic to the Navajo Nation.

Now, the situation is even dicier. This is a phrase we will no doubt hear more of — “fleeting exposure.” From Australia, where contact tracing is taken more seriously, journalist Josh Taylor wrote:

NSW health minister Brad Hazzard said the Delta variant which is behind this outbreak is a “near and present danger” given the fleeting contact between cases at the Bondi Junction Westfield.

This refers to a case in Sydney where there no was contact between two individuals who simply walked past each other in a department store — yet one of them caught Delta-brand COVID from the other. And then, it happened again:

The new case is the second person thought to have been infected by only “fleeting contact” with an infectious person, after a woman in her 70s tested positive on Thursday for only sitting outside a cafe the initial case had visited.

The city responded by making masks mandatory on public transport for five days and strongly recommended their use in any indoor setting. In other countries, some areas and jurisdictions that had contemplated loosening up suddenly decided it would be prudent to stay tight. In the United Kingdom, the Delta variant accounts for almost every current case, and fully vaccinated people make up 10% of the COVID hospital admissions.

This is not the fault of the vaccine, which does the best job it can with the information that was known when it was produced. The virus mutates like crazy; it’s like watching a speeded-up movie of the evolution of life on earth — from one-celled organisms to dinosaurs in 3.5 seconds. Human ingenuity is eating dust.

In Israel, there have been two extensive Delta outbreaks in public schools, with the infected people including some fully vaccinated grownups. Speaking of Delta on Twitter, Dr. Eric Feigl-Ding states that…

It is surging exponentially in the US at now 31% of all cases, up from ~10% just a week ago. It is high time CDC takes decisive action. That’s why @endCOVID19 & @CovidActionGrp are petitioning CDC to “reinstate mask-wearing indoors regardless of vaccine status, guidance for vaccination verification, & resume breakthrough case identification.”

Your responses and feedback are welcome!

Source: “The pandemic isn’t over yet,”, 06/04/21
Source: “NSW Covid outbreak: three new Sydney cases of ’near and present danger’ Delta variant recorded,”, 06/18/21
Source: “Masks compulsory on Sydney public transport after new ‘fleeting contact’ case,”, 06/18/21
Source: “In 2nd school outbreak, 44 kids catch COVID — apparently the Delta variant,”, 06/19/21
Source: “DrEricDing,”, 06/20/21
Image by Richard Harvey/CC BY 2.0

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OVERWEIGHT: What Kids Say explores the obesity problem from the often-overlooked perspective of children struggling with being overweight.

About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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