[M T]

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:

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.

[M T]

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:

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.