For the purposes of contact tracing and notifying South Dakotans that they have been exposed to someone who has tested positive for coronavirus, our Department of Health has defined “close contact” as being within six feet of the person who tests positive for fifteen minutes or more.
That shaky definition has left room for some school districts to game that definition by saying that close contact requires fifteen continuous minutes of within-breathing-distance interaction. They’ve said that students and teachers can interact throughout an entire class period or an entire day without triggering the “close contact” standard, as long as they only engage for five or ten or fourteen minutes at a time, then move around before interacting again.
The Groton School District suggests this tricky interpretation in its close contact language: “If your child has been within 6 feet of a COVID-19 positive individual for a period of fifteen minutes or longer, they [sic] will be considered a ‘close contact’….” “A period” seems to exclude the possibility of ten minutes in English class, ten minutes in Algebra, ten minutes at lunch, and two ten-minute interactions in the library.
The Huron School District’s School Re-Entry Plan (their website isn’t responding this morning, so I’m linking to the Google cache) refers to “timed interactions” in which students and teachers “move and reset prior to any 15 minute continuous interaction.”
The Agar-Blunt-Onida School District defined close contact as “Anyone who has had 15 minutes of consecutive exposure within 6’….”
The CDC now says those interpretations are out. Fifteen minutes now means fifteen minutes throughout the day, because new research says brief interactions can add up and spread coronavirus:
The CDC now defines a close contact as someone who was within 6 feet of an infected person for a total of 15 minutes or more over a 24-hour period.
…In a study published Wednesday, the CDC and Vermont health officials found that multiple, short and nonconsecutive exposures to persons confirmed to have COVID-19 led to transmission of the virus.
During the contact tracing investigation, it was discovered that the coronavirus was transmitted to a correctional facility employee who interacted with persons later found to be positive for COVID-19. The employee had 22 interactions totaling 17 minutes during an 8-hour shift.
Some of the employee’s contacts with those later found to have COVID-19 occurred when the COVID-19-positive persons were not wearing face masks. The CDC says the finding “highlights again the importance of wearing face masks to prevent transmission” [Joe Neel and Barbara Campbell, “CDC Reduces Consecutive Minutes of Covid-19 Exposure Needed to Be a ‘Close Contact’,” NPR, 2020.10.21].
Even with this evidence-based clarification of what constitutes “close contact,” keep in mind that six-feet-fifteen-minutes doesn’t mean that you’re guaranteed to get sick if you meet that criterion and guaranteed not to get sick if you run away after 14:45 and don’t chat again until tomorrow. It’s just a dividing line to make contact-tracing manageable:
Experts have long noted that the 15-minute, within-six-feet rule was not some sort of threshold that needed to be hit for transmission to occur. So much about whether spread happens depends on how infectious a person is, how well-ventilated the room that people are in is, how the virus might move through the air in a particular setting, whether people are wearing masks, and more. The 15-minute window had just been used as a benchmark to prioritize who should be followed up with for contact tracing and quarantine.
One reason why the length of interactions might matter, experts think, is because people need to be exposed to a certain level of virus if they’re going to get infected. Researchers still aren’t sure what that “infectious dose” is — and if a higher dose corresponds to how sick people are likely to get — but the thought is that the longer someone is around someone else who is infectious, the higher level of virus they will be subjected to, and the more likely they are to get Covid-19 [Andrew Joseph, “CDC Expands Definition of ‘Close Contacts,’ After Study Suggests Covid-19 Can Be Passed in Brief Interactions,” Stat, 2020.10.21].
Preventing coronavirus isn’t about gaming numbers and definitions. It’s about being careful all the time, reducing interactions, wearing a mask, and washing your hands. If schools don’t want to be even more overloaded with contact tracing and calls, they’ll need to take this clarified definition of close contact seriously and reduce close contact.
https://www.nbcnews.com/news/us-news/coronavirus-case-increase-sets-new-u-s-record-rising-over-n1244490
drumpf basically told the world last night he wants the ACA gone and has no plan to replace it. Let us all thank the incompetent Boobsey Twins, drumpf and Noem Nothing for making America a hell on Earth.
Close contact definition games are being played in schools. It is hinted at in the Huron wording Cory references, but schools are instructing teachers to have students move every 14 minutes so that there can be no “close contact interactions” as defined by the 15 minute rule interpreted as being continuous. I have also been told the same game is being played on busses in other districts. Seriously, it is like some districts have implemented their version of the 5-second rule for food falling on the floor for our children’s and teachers’ health in the most interactive environment we have in our communities.
Interesting debate last night.
Question… Is South Dakota “turning the corner” on the coronavirus too?
James,
I believe we are turning a corner; the situation is, I also believe, it is a blind corner.
James –
Turning a corner – yes.
We are moving rapidly from bad to dramatically worse.
During the week of the 15-21st of October we had more cases than we did during the entire month of August.
In one week.
We had the same deaths as we did during the month of August.
For the month of October, we have the second highest per-capita infection rate and the third highest death rate.
I guess “At Least We Are Not North Dakota” can be the new state motto…
(If you want, I can give you the actual numbers – I have written a script to pull the raw infection and death data from the CDC and put it into a SQL database so I can do data analysis. That’s like a totally normal, not at all strange thing for someone to do, right?)
Think about the really strange ways people are behaving, playing games with a highly Infectious, very dangerous virus.
Escalating levels of craziness. It’s bizarre. Historians are going to lose their minds over this.
Check out the world series tonight. Guys have flown in from all over the nation to joins 4-5s of friends, big indoor stadium…not many masks visible in group selfies…many players in dugouts shoulder to shoulder chatting for two hours…a few with masks. Coaches, masks down, instructing every batter, pitchers in the bullpen shoulder to shoulder… only a few masks. Will these games super spread. Is it really necessary to risk illness and death for corporate profits.
These fans will go home. Their families will travel to RC. To meet newborn and new young families traveling in from other states to be here.
Mr. Renli, grudznick has written a script to produce analytics on your self-proclaimed “computer 5k1Llz” and found them to be nearly on the level of the sabermetrics the Tampa baseball club is using in the world series.