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The Santa Clara, CA, population study showed 50x-80x more penetration than the 1100 confirmed positive cases reported on Apr 4. A couple more studies are showing similar penetration. /1 /thread
First, a similar antibody population survey conducted by USC for Los Angeles County, CA, shows a 28x-50x more penetration of infected people to the 7994 confirmed positive cases. This translates to 96.4%-98.2% of infected people are asymptomatic. /2
http://publichealth.lacounty.gov/phcommon/public/media/mediapubhpdetail.cfm?prid=2328
http://publichealth.lacounty.gov/phcommon/public/media/mediapubhpdetail.cfm?prid=2328
This also suggests a death rate of infected people of 0.14% => 0.27% (600 deaths/442,000 infected => 600 deaths/221,000 infected). Again, death rate similar to flu but infection rate much higher than flu. /3
Dr. Birx cautioned drawing conclusions from this study (and Santa Clara) in today's (4/20) briefing, citing the 1% error margin. But if you take the low end of the band to frame it conservatively, the error rate is fully accounted for => asymptomatic: 96.4%, death rate: 0.27%. /4
In an Ohio corrections facility, 1828 prisoners out of appx 2500 tested positive for COVID-19. Isolation/quarantine just started today, so we assume that during the spread, little mitigation was taking place. 1828/2500=>73% infection penetration!! /5 https://nypost.com/2020/04/20/more-than-1800-inmates-test-positive-for-coronavirus-at-ohio-prison/
So, if there is enough exposure in close enclosed quarters with little mitigation, it seems to continue to penetrate. The Diamond Princess cruise ship was more hopeful as in a close quarters situation there was only 20% penetration. But we have to follow the data. /6
With regard to mitigation, the stay-at-home and stay-inside directives may be better advice than travel into NYC by subway, but may have a couple of fundamental flaws. A new study says outbreaks of 3 or more cases most often come from the home. Oops! /7 https://www.medrxiv.org/content/10.1101/2020.04.04.20053058v1
It may be that the guidance should be to get outside in the sun and exercise -- two activities known to improve mental and physical health including aiding immune system. Of course, practice good hygiene and social distancing, but get out of the house. /8 https://www.theatlantic.com/health/archive/2020/04/closing-parks-ineffective-pandemic-theater/609580/
Still working on follow-on thread to Santa Clara, CA study, to see if there was an initial outbreak in CA that went undetected. /END
