Snorlax got his post up as I was writing mine... So I've removed the overlap
Quote:...
The city gave no metrics for whether it was successfully persuading those contacted to get tested or to quarantine.
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[[The head of the tracing program] added that he believed that the tracers would be more successful when they start going to people’s homes in the next week or two, rather than just relying on communication over the phone. [Yes, they're going to ask contact tracers to go into homes of people that just got a positive test. With all the concern about privacy, they're going to send someone cloaked in PPE to your front door! What an opportunity for strong-arm robbers. I will be surprised if they exceed 35% access rate that way.]
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A question I would like to ask in Santa Clara County (or anywhere): Of the positive cases, what percent were taking the test because they had been notified through contact tracing that they were exposed and should quarantine and get tested. In other words, is contact tracing catching 1% or 99% of the new cases?
When person A gets the disease, and they contact A's close contact B, do they either get B's close contacts or alert B that he should prepare a list of close contacts? [3 scenarios: A and B got it at the same time; B gets it from A; or A got it from B (who doesn't know or doesn't want to admit he has it)]
Btw,
Britain isn't having much success at contact tracing so far either.
I think contact tracing might work better if the patient is offered the opportunity (& guidance) to be the first to call his close contacts. I might not answer a strange phone number, but if a co-worker contacted me by email, or a friend by phone or text, I'd be more likely to see what is in the message. But everything I've seen appears to be treating COVID-19 like some shameful thing you don't want anyone to know you got.
(I've had two people, a co-worker and a person I only interacted with over the phone, be unavailable for two weeks. Duh, I wonder what that could be.)
That's the wrong message, IMO. If I were to get COVID-19, I'd probably be extremely diligent in contacting anyone I had been in contact with, at least for the people I knew. I'd care for their well-being, and more importantly, for the well-being of those around them. If I infected a co-worker, I can't prevent him from getting sick, but maybe I can alert him so he doesn't infect a parent. I'd think enlisting those patients that are willing would be a very effective method of contacting the contacts. Sure, the professional contact tracers can follow up with details about when to get (re)tested, programs to help with those infected, etc.
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Too Slow?
If contact tracing is to be most effective, it must catch the secondary infections before they become infectious. For it to be of much use at all, it should catch the secondary infections before they would already have symptoms and would already have taken the tests.
Suppose A was exposed on June 1, became infectious on June 4, gets symptoms on June 6, takes the test on June 7, and the results come back on June 8 (or June 9). Suppose B was infected by A on June 4, he well could be infectious on June 7, and gets symptoms on June 9.
The contact tracer may get to this case on June 8 (or, maybe not until June 9). Then they have to contact A (in NYC, 15% didn't give phone numbers), tell him the news, and get a list of names. (Quick, can you tell me everyone you spent 15 minutes within 6' (that's their definition of who is a close contact) over the last 14 days? What about that guy at the next table in the LA bar?) Then he's got to track down B (and any others), and then contact B.
It doesn't seem likely he'd get to B before he already infected people (and they infect others before they're contacted too), and quite possibly until after B already has shown symptoms and taken the test himself.
This seems WAY too slow for this disease. I'd argue that there should be 7x24 testing widely advertised (not every site, but perhaps at every 24hr ER) to eliminate the half day or more waiting overnight for half the cases to wait for testing to be open (when the patient doesn't have to be at work). There should not be 39 hours to get the test results as SCC is reporting. I would guess a bunch of that is waiting for samples to be sent from collection to the lab.
I'd still like to know why California is not adopting the Apple/Google app. Not that it is a panacea, but it can speed things up, and find contacts not given to the tracer.