Pritzker talks contact tracing
Friday, Nov 6, 2020 - Posted by Rich Miller
* This is being distributed by the governor’s office…
A press release is coming on this, but the governor explained today that outside Cook County and Chicago, contact tracers were able to reach 90 percent of those who test positive. The city and the county have real issues that need to be fixed. I’ll be updating as he goes along.
* He talked about outbreaks and exposures…
These are two words that get thrown around incorrectly, a lot, but they actually have very specific distinct meanings in public health. To start, let’s talk about an outbreak.
The location of an outbreak is more difficult to identify than the location of an exposure. An outbreak is defined as five or more cases that are linked to a specific setting during a 14 day period. Linked cases must be from different households and not already connected from other sources. And while certain settings like a college campus a factory or group home may make it easier to determine an outbreak, most establishments that are frequented by the public like restaurants, or grocery stores are not easily determined as the setting of an outbreak, based upon those rules. Add on to that that this disease is a respiratory in nature and a person might take some time before they start to show symptoms. And you can see why where outbreaks occur is important information, but far from the whole picture.
Please pardon all transcription errors.
* Exposures…
Much more useful for identifying regular locations that amplify the spread of the virus is exposure data. Particularly useful for the average person who wants to design their day to day in a way that reduces the highest risks.
Exposure data comes from contact tracers talking to confirmed positive covid patients about the places that they went in the time before they were symptomatic or tested positive for. For most people, especially those who don’t have the ability to work from home. That’s going to amount to multiple locations.
The day before a person tested positive for example, she might go to work, and then stop at a grocery store, and then stop and get drinks with friends at a bar that’s three exposure locations, and that’s just one day. Why is this important? Because exposure data is going to give you a sense of where you’re at the greatest risk for catching COVID-19, and particularly when we see community transmission as high as it is around the state, the risk is going to scale up across the board. Remember, masks are vitally important and the best tool for reducing risk but even with a mask. You don’t eliminate risk, especially when the inside in proximity to other people. And when you’re taking your mask off in public to eat, or to drink, or even to chat. You’re upping your risk.
So here’s our exposure data, to date, in Illinois, as you would guess workplaces in schools are going to be big. Because anyone reporting to their workplace every day, or any student or teacher engaged in in person learning, who tested positive is probably going to list school or work as a place they were before they tested positive.
But the single largest category of exposure locations statewide is restaurants and bars. And we see similar trends on a region by region basis, which you can review on the IDPH website. This aligns with the CDC study that came out earlier this fall. The study shows that when a COVID positive person could not identify a close contact that may have given them they were twice as likely to report dining in a restaurant in the two weeks prior to diagnosis.
These are facts. And if the facts change we can change our response, but all the data we have so far. points to these locations where people move, remove their masks in close contact for an extended period of time, as a major source of risk and, frankly, importantly, our mitigation plans, reflect the fact that those are a major source of risk.
* School exposure data…
Moving to school exposure data. I know the size of that school column on the exposure sites might alarm some parents. So I want to offer a couple of caveats on this data.
First, this is exposure data, not necessarily the exact location where a student or teacher actually contracted COVID-19. Anyone who goes into a school building regularly would have likely reported school as a place they went before they became a confirmed positive. That doesn’t at all mean that school is where they contracted the disease originally. And remember that masks are required in school and are not intended to be removed for extended periods of time.
Second, while we have school based data broken out by school on our website, this is exposure data that comes through contact tracings at local health department’s. The best data for any one specific school will come from the area local public health department. Schools are required to let parents and local health officials know about any positive cases. In terms of school outbreaks we have 10 schools that have currently reported confirmed COVID-19 outbreaks across the state. Again local health departments will be the best source of information on any specific school.
These outbreaks do not include secondary cases that may occur in a household among a household member who’s not been on the school grounds, but they do include those associated with before and after school programs like sports.
* Back to outbreaks…
In our statewide outbreak data we see a pattern of formal group gatherings, making up the majority of our confirmed outbreaks. Again, these are the settings where it’s easiest to trace the origins of someone’s illness and declare a situation a formal outbreak. I mentioned that the reasons why outbreaks are difficult to pin down, and I’ll add that with rates of spread the way they are right now, it’s only going to get harder, because this disease isn’t concentrated. Right now, it’s widespread.
…Adding… The promised press release is here.
- Keyrock - Friday, Nov 6, 20 @ 2:41 pm:
I guess he’s heard the comments on this blog (and elsewhere). It’s good to see the discussion.
- Captain Obvious - Friday, Nov 6, 20 @ 3:12 pm:
I will worry most about outbreaks. Interesting they claim highest risk of exposure in restaurants/bars but that is in no way substantiated by the data on traceable outbreaks.
- Rich Miller - Friday, Nov 6, 20 @ 3:17 pm:
===I will worry most about outbreaks===
Of course you will because it feeds into your ideological talking points.
- Thomas Paine - Friday, Nov 6, 20 @ 3:31 pm:
The standard for contact tracing is for the infected person to be contacted and their contacts traced within 48 hours.
It does no good to talk to someone four days later.
56 percent is not good at all, especially when that’s only 2/3 of the state, but of those do we know how many were contacted in 48 hours?
- DuPage Saint - Friday, Nov 6, 20 @ 3:40 pm:
This is not a snark and I am not trying to be funny but if there are 9 or ten thousand new cases a day and say each person met with ten people while infected, statistically shouldn’t we all be exposed soon?
- very old soil - Friday, Nov 6, 20 @ 3:44 pm:
And that’s why everyone should wear a mask, socially distance and avoid crowded places
- Jibba - Friday, Nov 6, 20 @ 3:56 pm:
Of the outbreak locations, the only places where you must remove your mask are bars and restaurants. Makes sense to target them first.
- Mike in central illinois - Friday, Nov 6, 20 @ 4:23 pm:
Let’s ask the governor why his state workers can’t work and sit home paid? Why keep beating up legitimate businesses and passing the blame to them. People will get sick, people will get better, if not they may perish. Outta your control, I’ve had it, my families had it,,I go to work in it every day,,,yet watch state workers sit home. Where’s your family JB?
- Consistency - Friday, Nov 6, 20 @ 4:38 pm:
In a previous chart they provided on October 5th, the category of “other” was labeled as the single highest “category” of exposure/contact.
At the time “other” was identified as a catchall for anything not covered by the specific categories, including things like vacations, family gatherings, weddings, and college parties.
This is not reflected in the current chart/metrics. It would be nice to get an explanation of the change even if the explanation is that they separated out the locations within the “other” category to let them stand on their own.
https://capitolfax.com/2020/10/05/state-contact-tracing-identifies-restaurantsbars-as-top-single-covid-19-suspected-source-followed-by-non-office-workplaces/