I wanted to draw your attention to a piece at RealClearScience that I found thought-provoking. It’s long and a bit hard to excerpt meaningfully but bear with me. Written by a physician in Hawaii it takes as its point of departure this anecdote:
What most caught my interest back in April were the reports from some of the seemingly worst places to catch Covid-19 — prisons and meat processing plants — showing that well over 90% of those testing positive were displaying no symptoms whatsoever. How could this reconcile with a disease we were told had only a 40% asymptomatic rate? The question literally kept me up some nights; and finally I decided that it must have to do with “cafeteria settingsâ€: all these places shared the common feature of large congregate gatherings in big spaces with shared air.
Like many of the theories that have been cooked up by non-epidemiologists in the past six months, this one had holes in it. That was made clear to me last month in a disturbing outbreak in my home state. An airline training, with reports suggesting a median participant age in the 30s, held in a very large room, with appropriately distanced desks, and masks used during interactive sessions, resulted in at least 6 of the 8 positive cases being significantly symptomatic, with 1 of the 8 students hospitalized, and another dying. Why did this congregate setting lead to such severe disease?
Studying outliers can get an amateur statistician into trouble. However, when apparent outliers are not anomalies but rather quite common, it is time to adjust our perspective.
and is in essence a speculation about this:
…studying how asymptomatic outbreaks differ from severe outbreaks might point us towards the most important ways we can soften future waves of this pandemic. Covid-19 cases are going to happen. Manipulating them toward being mild cases could be our goal. Understanding the environments that have been associated with the highest rates of asymptomatic Covid-19 could allow Americans to gather together to work and study without the level of illness and death we have seen thus far.
Others might find it less thought-provoking than subversive or wrong-headed. I’ll be interested in reading the reactions of others.
As usual the inevitable question that came to me from the piece was, if true what are the policy implications? Of this I am unsure at this point but it certainly looks to me as though, if the author’s conjectures are true, we’ve been going in the wrong direction for some time.
The second question that frequently occurs to me is how would you go about disproving the author’s conjectures? I’ll be interested in getting some ideas about that as well.
Structures are designed to minimize heating and cooling costs. Future health department regulation may have something to say about that, as with legionnaires disease.
This is a thought provoking article and it seems answers should be in the clues somewhere but I’m not the guy.
Also though, it comes to my mind that meat packing plants cooled to 40 degrees should be sealed with little ventilation for economic reason, but that may not be the case as I’ve never been inside of one.
This is the kind of stuff we sit around and speculate on in our office. The virus seems to behave in wildly different ways in different places. Not clear why. The asymptomatic part makes it really hard to study, and sometimes people blend in presymptomatic in discussions which makes it confusing. (Also lets the stupid and disingenuous make false claims.) We already knew that an infectious disease that was asymptomatic but could infect someone who would then become symptomatic would be a big problem, just like one that that would have a long presymptomatic period but was infectious during that period.
Before telling you how I would sum this up, I would note that an awful lot of these case studies have fairly low numbers and all are retrospective. So when the author cites statistical anomalies this is exactly where we find them. People who dont know statistics and/or medicine get all excited about a study with 40 patients showing a lot of success. Those of us who understand the above say that it is interesting and we need a real study.
My WAG, we need studies, is that I mentioned from earlier studies and observations is that in many ways we dont catch this virus that easily, not like measles. It takes the right conditions and when those are met we catch it easily but if those are not met we can still catch but it is uncommon. It looks like being outside is low risk. It looks like poor ventilation is bad. Humidity may be a factor. Absolute virus load may be important. (Super spreaders with high viral loads, or staying in prolonged contact with someone who is shedding.)
Steve
The Germans; as usual; are systematically trying to figure out if the author’s ideas have merit.
https://www.cnn.com/travel/article/germany-coronavirus-tim-bendzko-concert-wellness-scn-grm-intl/index.html
‘Absolute virus load may be important. (Super spreaders with high viral loads, or staying in prolonged contact with someone who is shedding)’
You’re the doctor, not me, but absolute viral load seems to be a VERY important factor in these deadly atypical situations. Makes sense. A bit like you accidentally breathing in a little water will make you cough and choke, whereas being dropped in the middle of a lake will cause you to drown. And the wearing of masks by previously uninfected people in enclosed areas with asymptomatic shedding carriers may compound the problem. All speculation on my part.
Population vulnerabilities should be strong directional guideposts in how to respond to this virus – people over 70, number of co-morbidities negatively effecting the immune system and blood vessels, ethnicity are factors warranting greater protective measures. Those not falling within such age, health or cultural perimeters should be treated with less public health scrutiny or limitations.
Other observations about this virus is that high temperatures, UV exposure, exterior conditions decrease the chances of transmission. The virus does not survive long on surfaces. Acknowledging this might reduce the frenzied need of disinfecting everything every minute.
T cell immunity is better than antibody immunity, and the former may be more relevant in explaining why so many present as asymptomatic. Also, 40% of the population may already have said T cell immunity, advancing the possibility that achieving natural herd immunity is not all that impossible, given more flexible social conditions.
Like others have said here, virus load is an important element in transmitting the virus and it’s degree of contagion in certain settings. For instance, children have been said to carry a smaller virus load, which may account why so few have died from this virus as compared to influenza. That also may be why numerous schools in Europe have reopened successfully, and under few of the limitations we are demanding here. Why are we digging in so much to keep schools closed?