Our social distancing guidelines are underthought

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Seriously under-thought.

One way Covid-19 spread is you shove your hand in your mouth, then you use your hand to gob onto a door knob, then the next person to come along licks the door knob. So don’t do that!

If you think I’m being silly, watch some pre-schoolers for a while.

But even adults, at a somewhat lower rate, continuously shed their sheddable viruses a little at a time onto every surface, where the viruses either die over a period of a few hours or get picked up by the next person.

So imagine a scenario in which a person is sitting in a room and a stream of people come in, one at a time, to socially distance at 6 feet away, masked, to have a conversation with that person. Further, imagine the person sitting in place is a teacher, and the visitors are little kids getting to meet their teacher before a semester of distance learning.

Sounds totally safe. Indoors, six foot distance, masks. Nothing can possibly go wrong.

OK, now lets backtrack and find the student in the parking lot. The student and her brother and two parents have just parked. They are coming from a sports event they’ve been attending weekly for a month, at which everyone is shouting and no one is wearing a mask. The are all infected but don’t know it yet. The family heads for the school, and let themselves in the front door. Four people have now touched the doorknob. They are now in the lobby and a school employee, masked and with a face shield, stops them and says, “OK, you’all stay here in the lobby but six feet away from the other families, and I’ll walk little sally to see Mr. Scary the teacher.”

While the student is away, the family gravitates over to some people they know, and start a conversation at what they think is a safe 6 foot distance, but they forget, don’t pay attention, whatever, and pretty soon they are closing in and talking around their masks at each other. Family 2 is now exposed, and has, say, a 1 in 30 chance of getting the virus. This scenario is, of course, playing out hundreds of times across the school district, so there will be some transmission at the door knobs and in the lobby. In the parking lot outside, even.

Little Sally is now being accompanied down an empty hallway by a person she does not know wearing a face shield and a mask, and she starts to cry (= major shedding) on the way down the hall and needs to have her hand held for the last few meters going into the room. While talking to her teacher she is overwrought being away from her parents in this strange place so she throws up breakfast. But that’s OK, the teacher and a para clean it up. But, remember, Little Sally is a carrier, so there is now a thin film of Covid-19 kooties from the lobby to the classroom, even where the hasty cleanup (everyone is behind schedule) happens. This is the first of a four day meet and greet, with two days this week, and two days next week. So this gives Mr. Scary and the para plenty of time to become contagious. So, on week two, one in 100 kids that come in to meet their teacher picks up Covid-19. That is’t many. But the school district has 10 elementary schools, and this scenario is happening in all of them, for a total of 3,000 kiddos. So there are now 30 sick and shedding elementary students mostly doing distance learning at home and, slowly, one by one, killing off the grandparents.

If you don’t like that scenario, make up your own. The point is, masking up and staying 6 feet apart slows, but does not eliminate, infection. As we return to schools, even with precautions, this is going to happen. Everywhere.

And now there is new research that gives us a better idea of how a 6 foot social distance is an oversimplified concept that provides a false, and in this case, deadly, sense of security. More to the point: People think that if everyone “wears” a “mask” (did you notice the scare quotes there?) and stays “six feet” away from each other, than the chance of infection is zero. It isn’t. It never was.

The following nuance inducing graphic is from “Two metres or one: what is the evidence for physical distancing in covid-19?” by Jones, Qureshi, et all, just published.

Risk of SARS-CoV-2 transmission from asymptomatic people in different settings and for different occupation times, venting, and crowding levels (ignoring variation in susceptibility and viral shedding rates). Face covering refers to those for the general population and not high grade respirators. The grades are indicative of qualitative relative risk and do not represent a quantitative measure. Other factors not presented in these tables may also need to be taken into account when considering transmission risk, including viral load of an infected person and people’s susceptibility to infection. Coughing or sneezing, even if these are due to irritation or allergies while asymptomatic, would exacerbate risk of exposure across an indoor space, regardless of ventilation

I’m not going to provide much of a summary of the article. It is very readable and clear. Just click here and find it, read it yourself.

“Instead of single, fixed physical distance rules, we propose graded recommendations that better reflect the multiple factors that combine to determine risk. This would provide greater protection in the highest risk settings but also greater freedom in lower risk settings, potentially enabling a return towards normality in some aspects of social and economic life.

Key messages:

  • Current rules on safe physical distancing are based on outdated science
  • Distribution of viral particles is affected by numerous factors, including air flow
  • Evidence suggests SARS-CoV-2 may travel more than 2 m through activities such as coughing and shouting
  • Rules on distancing should reflect the multiple factors that affect risk, including ventilation, occupancy, and exposure time

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4 thoughts on “Our social distancing guidelines are underthought

  1. How about that – a managed herd immunity approach is being considered by the government:


    I am not alone after all.

    It makes sense – since it is happening naturally anyway. Protect the sick and elderly (which is what I have been saying), but get to herd immunity as fast as possible (trying to control numbers to keep hospitals at manageable levels). Makes sense to me.

    I see the Washington post is using a 1% fatality rate and 65% for herd immunity. I think the fatality rate is more like .5% (assuming 10X cases to detected cases ratio), and the latest science shows the herd immunity can be achieved from 10-24% level, because of the existing pool of partially immune people (T-cell immunity from prior corona-viruses). So their 2.13M deaths number is probably high. I am guessing 500k or so deaths, more likely, and it could even be smaller than that if we are lucky.

    Here is the dirty little secret – we don’t have a way to stop people from getting sick without the cure being worse than the disease. So all these deaths would have happened anyway – just stretched out over a longer period of time. Just look at the case numbers worldwide, and see that each country is struggling and the cases just keep mounting up anyway. It is irrational to blame any leader of any country for the deaths from COVID-19. So you can pretend that Trump is at fault for the 187,000 deaths if you want to – but most rational people don’t blame trump for a pandemic which is impacting every country on the planet. Shit happens and we just have to deal with it!

    If we already have 60 million cases (10 x the detected number of 6M), we are already at 18.18% – so pretty close to potential herd immunity (if the current science is correct). I guess we will see – because we will be at 24% long before we get a vaccine.

    It feels like the number of people infected from each sick person has been dropping in the NorthEastern part of the country. So maybe we are getting close to herd immunity there. The Western part of the country should be next, then the southern part and finally the midwest last. So we will see what happens.

    At least we will learn a lot about herd immunity for corona-viruses out of this pandemic and therefore will be better prepared for the next one.

  2. RickA

    It feels like the number of people infected from each sick person has been dropping in the NorthEastern part of the country. So maybe we are getting close to herd immunity there.

    Groan! Nowhere near for reasons detailed in a number of posts by a number of people with reliable sources and not the wishful thinking that you fixate on. You still do not understand herd immunity.

  3. “we don’t have a way to stop people from getting sick without the cure being worse than the disease”

    That’s not a dirty little secret, that’s complete bullshit. Par for the course from you.

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