View Single Post
Old 03-28-2020, 02:09 PM
DSeid's Avatar
DSeid is online now
Join Date: Sep 2001
Location: Chicago, IL
Posts: 24,007
Stranger - if this is a familiar path you've experienced in threads then perhaps you should consider the possibility regarding the common denominator?

Assuming that Stranger meant their "bowing out" there is, in my mind, still a need to address things stated by the poster as facts that are at best speculations that go against the current experts' assessments, which is of course fine to do, so long as you identify them as such.

The experts rather strong belief is that, outside of certain procedures which produce aerosols, transmission is mostly droplet transmission. Again fine to argue why one thinks the experts are mistaken, if one does think that, but one is doing a disservice to readers to state as if it is fact that transmission is by aerosols when expert opinion is very much NOT.

Again I defer to the WHO who believe that smallish studies can give reasonable confidence intervals on seroprevalence and that a study of 5% of Hubei (4.5 million people) is not needed to get a sense of how many have already had the disease and are presumed immune. By reported cases only 0.1% of Hubei had COVID-19. If a mere random 300 are tested and 20% are positive, then one might be unsure if the true seropositivity rate is 26 or 14%, but can state with high confidence that the true rate is at least one to 2 orders of magnitude greater than the reported case number.

The item that very much need correction though is on how herd immunity works. Models that predict herd immunity do NOT require homogenous mixing of the population. In point of fact most standard models if anything overweight the impact of children in spreading the disease because they are the Typhoid Marys of many infections: they have many more close, inclusive of physical contacts with others, both intra- and inter-generationally, than other age cohort individuals, and they literally spew out their germs over all surfaces they are near. Not specific to respiratory infections, but my old ID prof made it clear that if you are in a household with a child, especially one prechool aged or younger, just accept the fact that no matter how much clean there IS a microscopic layer of feces on every surface you touch. They are a very, likely the most important quarter to have not contagious, if such is conclusively proven to be the case. It is why, based on influenza dynamics, school closures are a standard part of the pandemic response kit.

It is well past the point for widespread RT-PCR testing, let alone contact tracing and testing, to be useful. We have reached the point where significantly symptomatic COVID-19 is more often a clinical diagnosis (especially given, in our region at least, the low rate of other viruses with similar presentations testing positive, with low influenza and RSV rates), and those numbers are not being collected. They are however quite large, many times larger than the number of confirmed cases. The number of minimally symptomatic to asymptomatic per each of those who would fit a clinical diagnosis is even more of a guess, even if it is an educated one. Population level seropositivity testing is going to be the only way to get any handle on that number now. (IMHO.)