Thread by @statesdj

Let’s get real on test/trace/isolate. We have ~30k new testing confirmed cases per day. That mean we actually have ~300k new cases per day. Contact tracking is a lot of work, and BLS says we only have about 56 community health workers
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bls.gov/oes/2018/may/o…

First let’s define the problem. Figure shows the amount of virus being shed from the day of onset of symptoms. For both mild and severe cases, it’s already decreasing when symptoms start
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nature.com/articles/s4159…

Presymptomatic viral shedding means you need to catch infected people quickly before they infect others. And SARSCOV2 is a highly contagious virus, you need to trace and isolate most of the infected contacts or it keeps spreading
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Contact tracking is a lot of work: contact the case, interview them to find everyone they interacted with over past 2 weeks, decide which of those contacts were significant risk of transmission, get in touch with contacts, get them tested
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Identifying some contacts may be easy (e.g. co-workers), but others will be much harder (who was near you on the bus last Monday), some may cooperate, some may fear social stigma, job loss or just be afraid and refuse
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Assuming a contact is cooperative, they need to come in, get tested and self-isolate until their test results are back. And if the test is positive, the process starts all over again
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The goal is to make all of this happen, successfully, before most of the infected contacts infect anyone. We’re already starting a day or more behind the 8-ball because our turnaround time for tests is a day or more
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And the false negative rate of viral tests may be as high as 15%.
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the-scientist.com/news-opinion/f…

All of the multiple potential points of failure add up (can’t find case, failed to mention contacts, can’t ID contact, contact won’t cooperate, false negative test, won’t self-isolate …). If the overall success rate isn’t 60-80%+, the virus spreads and the process fails
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Bottom line, with 56k community health workers, limited testing capacity, significant false negs, slow turnaround, uncooperative people and 300k new cases of COVID-19 a day, trace/test/isolate is doomed to failure. Sorry, but it is what it is
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So what’s the solution? The big problem is cross community spread by super spreaders. Within a family spread is going to happen, the key to control is to keep additional clusters from getting infected.
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Some people just shed huge amounts of virus, million of times more than others. If you look at it as the amount of virus shed into the environment, 99% of the virus is produced by the top 20% of the highest shedders
virologie-ccm.charite.de/fileadmin/user…
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https://twitter.com/statesdj/status/1256616135908380673?s=20