Wednesday, December 29, 2021

The city's claim of low in-school transmission is unreliable at best

Yesterday the Mayor and the NYC Health Commissioner Dave Chokshi held a press conference to announce revised safety protocols for NYC schools, with weakened quarantining requirements.  Instead, kids ill be sent home with testing kits if they were in close contact with a Covid positive classmate or teacher, and unless they test positive on day 1 and/or on day 5, they can continue to attend school.  

They also said that they will double the amount of random Covid testing in the schools (ostensibly 10% of students weekly at each school, to be increased to 20%; though the actual number of students is  often far less given that families have to opt into rather than opt out of testing).  

For more on the new protocols, see the DOE letter to parents here, and articles in Gothamist and Chalkbeat.

During the presser  and afterwards on twitter, Dr. Chokshi repeated the claim that more rigorous measures were not necessary, including testing students more frequently or before the resumption of school next week, as some experts have advised, since they had found in-school transmission to be extremely low: "Even if the rates were to become somewhat higher due to Omicron becoming dominant, we estimate that, in schools, about 98% of close contacts do not end up developing COVID-19."

I received the document below that City Hall is using to back up this 98% figure, prepared by Dr. Jay Varma, the Mayor's Senior Advisor for Public Health.

Some quick observations:

  1. I don’t see the figure 98% cited anywhere.
  2. The time period covered, October – December 2021, is mostly pre-Omicron and thus of doubtful relevance to current conditions in which this far more infectious variant prevails.  In fact, the document is entitled, "Interim Report on COVID-19 Transmission due to Delta Variant in New York City Public Schools."
  3. Since the DOE Situation Room has been dysfunctional, especially in recent weeks, overwhelmed by the sharp rise in Covid cases in schools according to many accounts, it is unclear how much tracking and tracing the city has managed to do that could accurately estimate how much in-school transmission has actually occurred.  

If you have additional thoughts, please leave your comments/observations below the document.  Thanks!

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