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Contact Tracing (primarily Bay Area) - M T - 06-29-2020

Differing articles today on Contact Tracing
SF Chronicle:  "Bay Area contact tracing shows early signs of success"
SJ Mercury News:  "Is contact tracing — key to COVID-19 fight — working?   ... Lack of transparency makes success hard to measure"

SF Chronicle:
Quote:Many local counties are approaching their goal of contacting 90% of the region’s positive cases, while others are still scrambling to ramp up their contact-tracing operations.
Even if people with the virus, and their subsequent contacts, pick up the phone, they may be reluctant to give personal information.
The California Department of Public Health set a goal of 10,000 contact tracers by July 1. So far, that number includes 3,000 county employees and 3,300 state workers deployed to counties for six to nine months.
San Francisco, Santa Clara, San Mateo, and Alameda are able to track nearly all cases with their current workforce, but are prepping for a possible case surge.
Alameda County’s 83 contact tracers were able to reach about 85% of cases as of Wednesday.
Marin County, which was swamped with new cases this week, reached 70% of confirmed cases and only 46% of their contacts in the past two weeks.
McCurdy of Marin County said data on confirmed cases from testing sites can take up to a week to come in. In Alameda, contact information is sometimes spotty, without a phone number or address...
Even if contact tracers have a number, not everyone answers an unknown incoming phone call. Santa Clara County’s main limiting factor in reaching most, but not all, cases, is the willingness of the public to share information...
The program [CalConnect, used by most Bay Area counties, but not SF] lists the caller ID on contact tracing calls as “CA COVID Team” and can also text and email.
For now, contact tracers may try the number of a confirmed case three times over the course of two days. Once someone picks up the phone, San Francisco’s refusal rate to participate is less than 2%. Marin County’s McCurdy said people have immediately hung up on him.
Even when people are on board with the idea of staying at home, many who are most vulnerable to the virus cannot do so safely if they live with others or can’t miss work. In San Francisco, only about 60% of people contacted through the program could adequately self-isolate.

SJ Mercury News:
Quote:That has alarmed some doctors in the Bay Area’s two most populous counties, Santa Clara and Alameda, who cite recent examples of infected or exposed patients who were never interviewed about their contacts or notified of their potential exposure.  [followed by xamples; a letter to Alameda Co.]
But it’s impossible to know whether the Bay Area’s two largest counties have been successful because their health officials — who have closely guarded much information about the virus — refuse to reveal how many people they do reach, and how quickly.
[Santa Clara County spokesman David Campos] said they reach most, but did not provide precise numbers or say how often the tracers make subsequent attempts.
Recent publicly available details from New York City Health and Hospitals illustrate the challenges of contact tracing in the Big Apple, one of the worst-hit U.S. cities. Of 7,584 reported COVID-19 cases from June 1-20, case investigators reached 82%, but just 37% provided at least one contact. The investigators reached 68% of the 6,672 identified contacts they were given.
San Francisco’s dashboard reports the percentage of new cases and their contacts that health officials reach — both currently 83%, short of the city’s 90% goal. But it doesn’t indicate how quickly the connections are made.
Santa Clara County has 501 case investigators and contact tracers, well over the 289 the state suggested, and plans to expand that force to nearly 1,000 by the end of July.
Alameda County has “nearly 100” case investigators and contact tracers, Balram said, less than half the 247 the state formula recommends.



RE: Contact Tracing (primarily Bay Area) - M T - 06-29-2020

Separating my comments from the above news articles...

Not everyone has caller ID.  I won't know if it is spammers or the contact tracers.  When their phone goes "click" indicating a call center, I may have hung up before their first word.

In yesterday's Santa Clara County District 5 telephone town hall, I had given this question to the operator, but they didn't get to me.  I left in a recording at the end of the call:
Quote:Given the speed of infection passing from one person to the next and the problem of presymptomatic infection, by the time contact tracers talk to a case, their contacts may be already infecting others.  That makes any delays in getting to those contacts critical.  Is SCC ever going to adopt a quicker, more reliable, more private, scalable, and cheaper contact tracing system such as the Apple/Google API for smart phones, or will it continue to do the manual contact tracing.

When composing the question, I was struck by how many advantages this tech tool has.  It doesn't, or shouldn't, supplant manual tracing, but I have to believe that it is However, while I've read a bit about the API (to understand its privacy implications), I don't fully know how the operation works (specifically, the trigger for the contact info to be posted).  ("contact info" is NOT personally identifiable information such as name or phone number or even any identifier that anyone has access to other than the contact's smart phone).


I forgot to suggest a "Contact Tracing Effectiveness Statistic" of % of new cases that had been actually contacted by some tracing team prior to taking the test.   I think I'll write SCC and ask that they provide this effectiveness statistic.

I am less interested in the (important) statistic of how fast they get to them because that doesn't entirely show the effectiveness.   The problem is, when does the clock start ticking.  Look how LA County words it:  "Percentage of COVID-19 cases that have follow-up investigation initiated within 1 day of assignment".  If this were "Percentage of COVID-19 cases that have follow-up investigation initiated within 4 days of sample", then it would be more meaningful.  

I see patterns in the data that suggests that the SCC DPH gets the test results about 4 days after the sample is taken (by relating the patterns in the number of tests by date of sample to % positives by when they get the results).  SCC indicates 1.7 days "turnaround time".  My guess is that turnaround time is some other measure and may not take into account, for instance, time for the sample to get to the lab.

---------
Another concern came to mind as I read the newspaper articles.  Counties are offering financial assistance with quarantine/isolation.  If you are some one who gets COVID and are contacted by the contact tracers, theoretically you might falsely add your, say, unemployed brother-in-law as a contact.  He then could take advantage of that assistance.

I don't know if the phone app has a way to validate (to the county) that you were indeed a contact.  I bet it does, but I didn't previously consider that people might claim they were contacts when they weren't.


RE: Contact Tracing (primarily Bay Area) - Farm93 - 06-29-2020

(06-29-2020, 11:02 AM)M T Wrote:  Separating my comments from the above news articles...

Not everyone has caller ID.  I won't know if it is spammers or the contact tracers.  When their phone goes "click" indicating a call center, I may have hung up before their first word.

In yesterday's Santa Clara County District 5 telephone town hall, I had given this question to the operator, but they didn't get to me.  I left in a recording at the end of the call:
Quote:Given the speed of infection passing from one person to the next and the problem of presymptomatic infection, by the time contact tracers talk to a case, their contacts may be already infecting others.  That makes any delays in getting to those contacts critical.  Is SCC ever going to adopt a quicker, more reliable, more private, scalable, and cheaper contact tracing system such as the Apple/Google API for smart phones, or will it continue to do the manual contact tracing.

When composing the question, I was struck by how many advantages this tech tool has.  It doesn't, or shouldn't, supplant manual tracing, but I have to believe that it is
  • quicker:  I am not sure, but I expect contacts are notified electronically as soon as the case's phone is told to post its contacts.  There is no delay in contacting the case, getting a list of contacts, or trying to call them
  • more reliable: It doesn't require one to remember who they were with.  It doesn't require one to know who they encountered.
  • more private: The case, the contact tracer, and the contact don't know the case AND contact.  That connection is not recorded.
  • scalable: SCC scaled contact tracing staff for 75 cases/day; LA County scaled for 2500 cases/day.  Both have exceeded that number of cases in a day.
  • cheaper: There will be a cost to set this up, but in terms of cost per contact told of the exposure, I have to believe this is cheaper.  I believe it will also be  cheaper if it can get more people into isolation quicker by reducing the number that get sick.
However, while I've read a bit about the API (to understand its privacy implications), I don't fully know how the operation works (specifically, the trigger for the contact info to be posted).  ("contact info" is NOT personally identifiable information such as name or phone number or even any identifier that anyone has access to other than the contact's smart phone).


I forgot to suggest a "Contact Tracing Effectiveness Statistic" of % of new cases that had been actually contacted by some tracing team prior to taking the test.   I think I'll write SCC and ask that they provide this effectiveness statistic.

I am less interested in the (important) statistic of how fast they get to them because that doesn't entirely show the effectiveness.   The problem is, when does the clock start ticking.  Look how LA County words it:  "Percentage of COVID-19 cases that have follow-up investigation initiated within 1 day of assignment".  If this were "Percentage of COVID-19 cases that have follow-up investigation initiated within 4 days of sample", then it would be more meaningful.  

I see patterns in the data that suggests that the SCC DPH gets the test results about 4 days after the sample is taken (by relating the patterns in the number of tests by date of sample to % positives by when they get the results).  SCC indicates 1.7 days "turnaround time".  My guess is that turnaround time is some other measure and may not take into account, for instance, time for the sample to get to the lab.

---------
Another concern came to mind as I read the newspaper articles.  Counties are offering financial assistance with quarantine/isolation.  If you are some one who gets COVID and are contacted by the contact tracers, theoretically you might falsely add your, say, unemployed brother-in-law as a contact.  He then could take advantage of that assistance.

I don't know if the phone app has a way to validate (to the county) that you were indeed a contact.  I bet it does, but I didn't previously consider that people might claim they were contacts when they weren't.

Text spam is a bit less common.  
Federal Government should make it clear that only government agencies can use some language at the front.
URGENT MESSAGE FROM USA GOVERNMENT REGARDING YOUR POTENTIAL EXPOSURE
Some that may have been in contact with you tested positive for COVID19 on (insert date).

The insert text on quarantine instructions and/or expedited testing at (insert facility)

Given the lines I have seen for testing, probably best to give those getting the text a code they can use to serve as some form of line fast pass.

Not only do we want these individuals to get tested, we also don't want them standing in lines to be tested.  

I really don't think I would respond to a call given the growth in cell phone spamming the last several years.   I almost certainly would not listed to a voice mail message.   Even if I did I would assume it was just spam to get me to a private site selling stuff.


RE: Contact Tracing (primarily Bay Area) - Goose - 06-29-2020

It is absolutely obvious (at least to me) that lots of personal visits to the home of people who test positive will be needed. This situation should finally demonstrate to the FCC why unsolicited robo-calls are destructive and must be eliminated. They make what once was an almost universally reliable form of communication useless. People just won't answer. It will require more people, but if the telephone call doesn't work, send someone to visit.


RE: Contact Tracing (primarily Bay Area) - burger - 06-29-2020

(06-29-2020, 02:27 PM)Goose Wrote:  It is absolutely obvious (at least to me) that lots of personal visits to the home of people who test positive will be needed. This situation should finally demonstrate to the FCC why unsolicited robo-calls are destructive and must be eliminated. They make what once was an almost universally reliable form of communication useless. People just won't answer. It will require more people, but if the telephone call doesn't work, send someone to visit.

This excellent article makes the same argument using syphilis contact tracing from the 50s as an example.  You can't just expect everybody to cooperate--you need contact tracing systems (and contact tracers--a point no one discusses) that are up to the job.

https://www.nytimes.com/2020/05/23/sunday-review/coronavirus-contact-tracing.html

This was obvious to me, you, and a lot of other people well before the contact tracing systems were put into place. Why have we done this so badly?


RE: Contact Tracing (primarily Bay Area) - M T - 06-29-2020

(06-29-2020, 02:56 PM)burger Wrote:  https://www.nytimes.com/2020/05/23/sunday-review/coronavirus-contact-tracing.html
From the article:
Quote:[part of a COVID tracer training course] recommends memorizing catchphrases to use during calls such as “I hear you” and “This is a difficult time.” That is, the kinds of canned responses that might send someone into a blind fury when calling tech support.

They have me pegged!  Be condescending or demonstrating you aren't listening by repeating platitudes and you're pushing my buttons.  The link above (to "Why Tech Support Is (Purposely) Unbearable")  is worthy too.   The most recent example for me is, in dealing with identity theft issues,  I set up an account to monitor my credit at one of the big 3 credit companies and the guy said "And now, for the secret so you can get back into your account if you forget your password, what is your mother's maiden name?"  I literally laughed out loud, and pointed out that info is generally trivial to get, and I'm here because someone's got a lot more than that.  "You'll have to do better than that."  I wonder if he felt a little embarrassed that it truly was a bad secret when identity theft is already present.  Maybe he was a bit flustered. So, he offered "What's your father's maiden name?"  (true story).  Sigh.


RE: Contact Tracing (primarily Bay Area) - M T - 07-07-2020

One of the tenets of contact tracing is that the system is trying to reduce both the number of infectious persons and the number of days they are infectious and out in the public.

Part of that is how quickly tests get back to the patient, and then to the contact tracing organization (usually the county).

I wonder if the US is imbalanced by emphasizing testing large numbers of people at the expense of taking longer on getting those tests back quickly.
This past weekend, we saw that testing companies weren't  getting results back over the holiday.   I guess the expense of paying staff to work holiday hours is more important than 1 more day of infectiousness for those who didn't have tests back.  (I am not talking about the LA County issue of switching to a new system, so they delayed posting numbers for 3 days.)

I was distressed by this:  https://youtu.be/sxvu83d2Eg4?t=329  (the speaker is one of the regulars on This Week In Virology)
In NY, tests were coming back in 48 hours, but then started taking longer, up to 5 days.  (The tests were being sent out of state because it was cheaper.)

I know anecdotal cases in Texas.  A healthcare worker a month ago had symptoms, and it took most of a week to get results back.
Last week, a healthcare worker (that I know) took a precautionary (no symptoms, no known exposure) test on Wednesday.  Antibodies came back negative, but as of 5 days later (Monday night), he didn't have PCR results when he found out someone he last worked with on Monday (7 days back), had a positive test.     The testing agency told him that his test was being sent to NJ ("because it was faster").    Not only is he potentially at risk, but so are the other people he saw over the 4th.

In SCC, a PHO order of SCC testing facilities requires results to be sent to the county within an hour.  I notice that doesn't require, say, Sacramento or NJ facilities to send the results to SCC in a timely manner, nor does it require the tests to be finished within 24 or 48 or even 96 hours of the sample.  

SCC reports a "turnaround time" of under 2 days, but I don't know how they define that.  I would hope it is time of sample to the later of when the patient or county is notified.  As I understand it, Stanford had been doing a lot of SCC testing.  The turnaround time bumped upward recently from 1.6 or so to 1.92, but potentially that is a one time blip due to the holiday.

Despite SCC's claim of <2 days, I see patterns in their data suggesting that receipt of results is about 4 days (and, previously, 5 days) after the day the sample is taken.  I do not feel confident enough to claim that is the case, but I'm hoping I'm wrong.

Of those that have had PCR tests, what are people's experiences in terms of time from sample to time of notification?


And, by the way, SCC's "Unknown cause" percentage is increasing while the "Contact to a known case" is decreasing (through July 7 update).


RE: Contact Tracing (primarily Bay Area) - Goose - 07-07-2020

(07-07-2020, 12:04 PM)M T Wrote:  One of the tenets of contact tracing is that the system is trying to reduce both the number of infectious persons and the number of days they are infectious and out in the public.


Part of that is how quickly tests get back to the patient, and then to the contact tracing organization (usually the county).

It could be argued that people waiting for their test result won't/shouldn't be out in public anway. The problem is that contact tracing isn't going to start until the positive test is returned. If the delay is less than the incubation period, it won't matter on "forward" traces, i.e. people who were exposed via the person being tested. It will matter on "backward" traces, i.e. the person who gave the virus to the person being tested. The "index case" will still be out there infecting people during this delay, especially is he/she is  asymptomatic or pre-symptomatic. It should be true that if one gives a sample on day N, the result is available by end of day N + 1. It appears that isn't happening. The reasons for any delays need to be examined. It isn't testing capacity. It probably is logistical, and those problems can and should be solved.
Quote:And, by the way, SCC's "Unknown cause" percentage is increasing while the "Contact to a known case" is decreasing (through July 7 update).
Triple OUCH! The number of contact tracers should be increasing, yet the results are getting worse, not better.