After that blizzard of charts that I finally got through with help from friends and readers, back to some research. Please note a couple of things, the Age Structure post had some mislabeled charts and has been updated. And I want to point out on the last chart, those percents of the population in an age group that have died, please note that it doesn’t cross even one-tenth of a percent until past age 70. Just reflects how non-deadly this pathogen is to almost everyone. I believe there actually is a podcast now on adaptive immunity. And next week I am giving a zoom presentation to the Edina Morningside Rotary Club on the epidemic. That presentation will be taped and available to the public and I will provide you all with a link. Finally, the holidays often screw things up, but watch cases reported on Wednesday and Thursday, which will reflect tests on Monday and to some extent Tuesday. You can see in the case table by specimen collection date that Monday tends to have the highest cases with declines through the week and low points on the weekend. If today and tomorrows case numbers are flat with last week, I suspect we will have peaked. Then we will see if we get a Thanksgiving swell.
This is an interesting article in Nature regarding the origins of this strain of CV. (Nature Article) At this point, despite the earlier warning signs from the original SARS and MERS viruses, coronaviruses in general are getting a lot of needed study. People are looking at stored animal samples to see what they can find that might be very similar to CV-19 and thus a predecessor. This article describes two findings of coronavirus strains in bat samples from Asia, one in Japan and one in Cambodia. The most interesting aspect of the findings is the indication that there may be a number of strains with a lot of similarity to CV-19, most of which are in East Asia and there likely has been significant human interaction with those viruses. I wonder on the one hand if that interaction with these similar strains means that Asians are much more likely in some countries to have pre-existing immune responses which limit infections. On the other hand, some places, like Wuhan, had pretty substantial epidemics. China will probably never be completely forthcoming on how extensive, but it appears to have been widespread. There is some explanation beyond supposed mitigation measures that explains the absence of infections in many East Asian countries.
I am trying to get more detail on this but I consider some of this research to be the most valuable. This is an abstract from a paper presented this weekend which dealt with the physical dynamics of spread of respiratory pathogens. (APS Abstract) And I did find what is likely the underlying article in Nature. (Nature Article) This underlying study dealt with influenza and involved a study of transmission in animals. What is fascinating about this study is that it helps explain why masks may not be that effective in some cases and how CV-19 seems to be so sneaky in its transmissibility. The authors identified what they called aerosolized fomites that may be present even on uninfected animals or surfaces and demonstrated that the flu virus appears able to be spread via those particles. In the case of the infected animal model, the animals contaminate their fur and their surroundings with virus and most of the aerosolized particles with virus actually arose from those sources not exhalations. The authors also showed that environmental surfaces could produce similar fomites, such as by rubbing tissues. These tend to be very small particles. If the virus can survive in these circumstances, it likely does have environmental niches and reservoirs in which it can survive and eventually spread. Now thing about virus collecting on masks and people touching those masks and doing other actions with them. And think about the virus being able to survive on carpets, curtains, other typical dust and particulate sources and then being stirred up. I am really hoping a lot more of this research is done so we can get a better answer about all the ways in which Cv-19 may be transmitted.
This is another attempt at elucidating factors which explain the variation in death rates across states. (SSRN Report) These rates have a very wide range. Factors examined included various population density, income, ethnic and racial, travel, mitigation measures and population health ones. They found that population density alone was the factor which explained much of the variation in mortality. The mitigation measures, including mask mandates, did not have a significant effect in this analysis. Race and ethnicity also were a factor, but no other variables reached significance.
This paper explores the impact of lockdown measures on health care utilization. (NBER Report) The authors used a database of claims from over 6 million people with employer-sponsored health insurance data to assess the effect stay-at-home orders on preventive care, elective care and number of weekly visits to doctors and hospitals at a county level. The authors found very large reductions in care, but when controlling for level of epidemic in the county, the effect diminished significantly. The authors somehow interpret this as people would have missed a lot of this care even without the orders. I don’t understand this reasoning. The lockdowns were accompanied by scaring the heck out of people and that caused them to miss care. Some of this is care that can be delayed but a lot is screenings like mammograms that make a huge difference in outcomes. Telemedicine made up some of the lost in-person care but not close to all of it. One interesting nugget was that hospital employment declined by over 135,000 people during the pandemic, due to loss of revenue. So when you read about hospital staffing issues, remember that the early terrorization and mandates around elective surgeries caused this. Government screws everything up, usually by unintended but predictable consequences.