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Question - lex24 - 06-24-2020

Im sure this is out there. Just want to find it- ratios of positives to number of tests over time. Calif is hitting record positives. Also record number of tests. One would think positive to test rate is an important stat.

The only comment I saw relating to Calif’s Tuesday’s record number is that the percentage of positive per tests is “slightly up.”

Isn’t that an important number to track? Is there a site I can track it on?

RE: Question - burger - 06-24-2020

Try here: https://public.tableau.com/profile/ckelly2528#!/vizhome/COVIDDashboard-Public/Introduction You can click through to the stage pages, or you can change the selector on the overview page to show only CA.

Positive rate in CA has been increasing recently. It's easier to see that the number of positive cases is increasing faster than the number of tests. So the spike in cases is not due to more testing.

[Image: LNWsHdc.png]

RE: Question - M T - 06-24-2020

Is that graph of positive % a rolling average, or a overall average? A rolling average (1 week or 2 week) is more informative as things change.

RE: Question - burger - 06-24-2020

(06-24-2020, 01:49 PM)M T Wrote: Is that graph of positive % a rolling average, or a overall average? A rolling average (1 week or 2 week) is more informative as things change.

Bars are daily results. Darker lines are 7-day averages.

RE: Question - chrisk - 06-24-2020

The news today was that positive cases jumped from 5K+ to a new record of 7K+. Although there was a big jump in the number of test, the positivity rate moved above 5%. They are treating 8% as a red line.

RE: Question - BostonCard - 06-24-2020

(06-24-2020, 01:04 PM)lex24 Wrote: Im sure this is out there. Just want to find it- ratios of positives to number of tests over time. Calif is hitting record positives. Also record number of tests. One would think positive to test rate is an important stat.

The only comment I saw relating to Calif’s Tuesday’s record number is that the percentage of positive per tests is “slightly up.”

Isn’t that an important number to track? Is there a site I can track it on?

Here's another tracker:

https://covidactnow.org/us/ca?s=56070

The dashboard is useful:

The estimated infection rate ® is above 1, but not by much.
The positive test rate is 5%. That's up from a trough of 3.8%.
ICU headroom used is up to 29%. That's plenty of room to handle a surge, but is up from 20% earlier.
Contact tracing is down from 30% to 21%, not a good trend.

BC

RE: Question - lex24 - 06-24-2020

Thanks.

RE: Question - burger - 06-24-2020

(06-24-2020, 02:37 PM)BostonCard Wrote:
(06-24-2020, 01:04 PM)lex24 Wrote: Im sure this is out there. Just want to find it- ratios of positives to number of tests over time. Calif is hitting record positives. Also record number of tests. One would think positive to test rate is an important stat.

The only comment I saw relating to Calif’s Tuesday’s record number is that the percentage of positive per tests is “slightly up.”

Isn’t that an important number to track? Is there a site I can track it on?

Here's another tracker:

https://covidactnow.org/us/ca?s=56070

The dashboard is useful:

The estimated infection rate ® is above 1, but not by much.
The positive test rate is 5%. That's up from a trough of 3.8%.
ICU headroom used is up to 29%. That's plenty of room to handle a surge, but is up from 20% earlier.
Contact tracing is down from 30% to 21%, not a good trend.

BC

These trackers that have pre-defined criteria for when things are good or bad concern me (the state uses similar metrics). For one thing, these mostly focus on levels, not rates of change. ICU % usage may be in the good range now, but if hospitalizations are increasing rapidly, that won't last for long.

Also, I would love to know how they're calculating R. If we're setting records for cases every day and the % of positive tests is increasing, I have trouble imagining how each case in California is only resulting in 1.05 new cases. I think that estimating R from these data is extremely difficult. The number of tests conducted is changing from day to day, so you have to account for that when estimating R. That raises another complication: what's the expectation for % positive as a function of the number of tests given? I have searched around for a discussion of this issue and found nothing so far. I'm sure that this can be modeled, but it would take a complicated model that incorporated the probability of getting tested as a function of the number of tests given and whether or not someone is infected. That would be a mess.

Ultimately, this does not have to be complicated. My dashboard would only have two questions: 1) is the number of cases going up faster than the number of tests? 2) Are hospitalizations increasing? If yes to both, you need to do more to get the virus under control.

RE: Question - Goose - 06-24-2020

(06-24-2020, 02:37 PM)BostonCard Wrote: Contact tracing is down from 30% to 21%, not a good trend.

BC

The contact tracing statistic is probably useless. It is based on how many contact tracers are employed in California, how many new cases there are, and a "standard" value of how many cases a day can be traced by one person. The first number, the number of contact tracers, is mostly a guess, because no jurisdiction I am aware of has really give a "straight" answer to the question. Second, the number of cases one can do in a day is a pretty conservative number. It may be close to correct, but at least in San Mateo County they claim they are doing the job with many fewer people. How many fewer depends on the degree to which the 85 "available" tracers are being called upon to help the 30(?) full time tracers.

Once again I have asked the San Mateo County health department to publish some information on how many "contacts" they are requesting to quarantine (per week would be fine) and how many of the "positive" tests were people already listed as "contacts". The answer I got back (again) was that they are thinking about what to release and that they want to do it in conjunction with the other Bay Area jurisdictions. I am not at all happy with this answer. They have had enough time. They have the data. One of the problems with the public's response to Public Health is IMHO the lack of real, transparent data about what is going on. We are relying on these people, and are expected to do what they demand of us. In order to get people to do so willingly, we need to see and hear about a plan that can work. So far, that is absent.

RE: Question - fullmetal - 06-24-2020

There are far too many new positive cases to effectively contact trace and preemptively quarantine (to have a visible/immediate impact). Not to say that it's not an important effort...stemming the tide of an exponential function is always meaningful, but we won't see significant results for a while. I think of it as plugging holes in the dike with fingers. Correct me if I'm wrong.

Gotta hire more tracers. Or lock it all down again and burn out the virus until contact tracing capability can deal with each day's new positive cases.

RE: Question - Goose - 06-25-2020

(06-24-2020, 11:46 PM)fullmetal Wrote: There are far too many new positive cases to effectively contact trace and preemptively quarantine (to have a visible/immediate impact). Not to say that it's not an important effort...stemming the tide of an exponential function is always meaningful, but we won't see significant results for a while. I think of it as plugging holes in the dike with fingers. Correct me if I'm wrong.

Gotta hire more tracers. Or lock it all down again and burn out the virus until contact tracing capability can deal with each day's new positive cases.

In Southern California, I think you are correct. However, San Mateo County claims they are contact tracing 100% of the cases in the county. They also say they are generally contacting out of jurisdiction people who show up as contacts, although sometimes they hand it off to the other jurisdiction if it isn't practical to do it directly. They are talking a real good game, and claim this has been going on the entire time we were in lockdown. So where are the new cases coming from? That is why I want some numbers from them, and I can't get any. Frustrating. If all/most of the new cases are spread from out of the county, we need to know this and get on the state to deal with this. If it is "local", something is rotten in Denmark.

RE: Question - Farm93 - 06-25-2020

(06-25-2020, 08:34 AM)Goose Wrote:
(06-24-2020, 11:46 PM)fullmetal Wrote: There are far too many new positive cases to effectively contact trace and preemptively quarantine (to have a visible/immediate impact). Not to say that it's not an important effort...stemming the tide of an exponential function is always meaningful, but we won't see significant results for a while. I think of it as plugging holes in the dike with fingers. Correct me if I'm wrong.

Gotta hire more tracers. Or lock it all down again and burn out the virus until contact tracing capability can deal with each day's new positive cases.

In Southern California, I think you are correct. However, San Mateo County claims they are contact tracing 100% of the cases in the county. They also say they are generally contacting out of jurisdiction people who show up as contacts, although sometimes they hand it off to the other jurisdiction if it isn't practical to do it directly. They are talking a real good game, and claim this has been going on the entire time we were in lockdown. So where are the new cases coming from? That is why I want some numbers from them, and I can't get any. Frustrating. If all/most of the new cases are spread from out of the county, we need to know this and get on the state to deal with this. If it is "local", something is rotten in Denmark.

I-5 and US-101

Sometimes the easiest answer is best. There are thousands of people that travel from the SF Bay Area to So Cal on those roads every day. Quite literally we have several bus operations and some charge as little as $20 one way. Gas is also cheap.

Also many that drive rather than fly will have reasons to not disclose their interactions with friends and associates to government agencies.

Tracing is really hard in the USA, and I don't think any state is doing it well enough for us to avoid a 1st wave resurgence this summer and/or a second wave this fall.

RE: Question - dabigv13 - 06-25-2020

The cat is out of the bag already. Contact tracing will not factor meaningfully into the US response in the vast majority of the US. There is broad community transmission in too many places, and no US location, perhaps with exception of Hawaii, got numbers low enough before reopening to really give themselves a shot at it.

Perhaps if we did not have 50 different states doing 50 different things, we could have pulled it off. It will be interesting what happens after we have second lockdowns. Will those locations reopen the next time more slowly to try and squash community transmission, or will it be another quick reopening to try and get some economic activity going, but then with prospect of a 3rd lockdown.

Texas stopping elective surgery in most major metros. California will probably have to do similar in next couple weeks. Govs say they don't want to lockdown, but it will come. Virus calls the shots.

RE: Question - M T - 06-25-2020

(06-25-2020, 08:34 AM)Goose Wrote:
(06-24-2020, 11:46 PM)fullmetal Wrote: There are far too many new positive cases to effectively contact trace and preemptively quarantine (to have a visible/immediate impact). ...

In Southern California, I think you are correct. However, San Mateo County claims they are contact tracing 100% of the cases in the county.

In its May 18 attestation as to why they should be allowed to open up faster, L.A. County claimed they were going to staff to handle 2500 cases a day

Quote:DPH anticipates an ongoing rise in the number of confirmed COVID-19 cases that will reach or exceed 2500 cases a day. In anticipation of a rise to this level, DPH projects needing approximately 2500 additional staff to support surge response in contact tracing. This projection is based on the following information: ...

They have exceeded 2500 earlier this week (as a high, not average). They claim "Percentage of COVID-19 cases that have follow-up investigation initiated within 1 day of assignment: 98.6%" Of course, "assigned" and "initiated" leave a lot of wiggle room. Is an outgoing text sufficient to be an initiation? Or, just doing a search for a phone number, or filing a report? I don't know. But the number of cases appear to continue to climb.

I would like to challenge every public health office and every state in the country to publish the stats of new cases that were contacted by tracing before getting a positive test.

=========

The US had an average of 566 reported COVID deaths per day in the last week. That's equal to the sum of the WWI and WWII US death rates.

RE: Question - BostonCard - 06-25-2020

I mean, this week end, I will be one of those. I'm taking my kids down to see my parents in San Diego for a week.

BC

RE: Question - Goose - 06-25-2020

(06-25-2020, 08:58 AM)Farm93 Wrote: I-5 and US-101

Sometimes the easiest answer is best. There are thousands of people that travel from the SF Bay Area to So Cal on those roads every day. Quite literally we have several bus operations and some charge as little as $20 one way. Gas is also cheap.

Also many that drive rather than fly will have reasons to not disclose their interactions with friends and associates to government agencies.

Tracing is really hard in the USA, and I don't think any state is doing it well enough for us to avoid a 1st wave resurgence this summer and/or a second wave this fall.

You could be correct. It is a reasonable possibility. However, it could also be (hypothetical) that San Francisco isn't doing enough tracing and lots of these cases are coming from there. What needs to be true is that we KNOW where they are coming from. San Mateo County says they are getting excellent cooperation from the public. If so, it isn't (hypothetical) drug delivery people doing the spreading. Whenever one sees a government entity saying they are meeting their requirements and yet the data doesn't seem to reflect that condition, it is very worrying.

RE: Question - Farm93 - 06-25-2020

(06-25-2020, 10:47 AM)Goose Wrote:
(06-25-2020, 08:58 AM)Farm93 Wrote: I-5 and US-101

Sometimes the easiest answer is best. There are thousands of people that travel from the SF Bay Area to So Cal on those roads every day. Quite literally we have several bus operations and some charge as little as $20 one way. Gas is also cheap.

Also many that drive rather than fly will have reasons to not disclose their interactions with friends and associates to government agencies.

Tracing is really hard in the USA, and I don't think any state is doing it well enough for us to avoid a 1st wave resurgence this summer and/or a second wave this fall.

You could be correct. It is a reasonable possibility. However, it could also be (hypothetical) that San Francisco isn't doing enough tracing and lots of these cases are coming from there. What needs to be true is that we KNOW where they are coming from. San Mateo County says they are getting excellent cooperation from the public. If so, it isn't (hypothetical) drug delivery people doing the spreading. Whenever one sees a government entity saying they are meeting their requirements and yet the data doesn't seem to reflect that condition, it is very worrying.

Not drugs...though I guess some of the traffic will be doing that too.

The traffic I was referencing was those that don't have government IDs for airport security, but can ride a bus, or those that are going to visit people without IDs. Amnesty seems to be sketchy at best in SF. I am confident the details of those types of visits would not be covered in detail with a San Mateo County tracing team employee.

Though you are definitely right that if one went down to SoCal for a drug run they definitely would not give out those details to a government tracing team.

Ultimately there is a lot of daily traffic between Northern and Southern California by trains, planes, buses and automobiles for either region to really think a problem in one region won't impact the other. For a number of legal and illegal reasons, and any of that traffic could bring the virus back to the SF Bay Area.

While it is important to try to trace, there is no way any county in California is tracing 100% of the cases accurately. There are just too many people that will want or need to hide contacts for all kinds of reasons, and I tend to doubt they are even getting 100% of those without anything to hide.

RE: Question - OutsiderFan - 06-26-2020

As for burger’s Ro question, how does Dr. Redfield’s assertion of 10x more infections than have been detected factor in? This assumption is based on antibody testing we know isn’t all that accurate, but still probably provide enough meaningful data to roughly estimate how many more infections there are than what PCR tests have revealed. Certainly better than a wild guess.