Thread by @smartrestartaps

#MaskUp in #Schools

nytimes.com/2021/08/10/opi…

2/☝️This shows about a 1% transmission rate while all kids were wearing masks in this study.
The caveat (in the earlier data we reviewed) was surveillance testing wasn’t utilized to catch many asymptomatic kids. In places where testing was used, like Omaha, they found 6x cases.

3/ Other studies found COVID-19 infected many more kids than known. Serology in MS found >10x COVID-19 cases in kids as known. (Many MS kids getting reinfected; devastating outcomes.)

INOVA/GMU study: HUGE undercount here.
Any known exposure = kid ~3x more likely infected

4/ Many of the cases weren’t severe, and flew under the radar. But COVID’s new, 2.4x more infectious virus is much more scary, because so many more will be infected; we get more of worst outcomes, and hospitals can easily be overwhelmed.

The personal stories are just shattering.

5/ Which brings us back to masking. No, you can’t say masks will prevent 99% of COVID-19 spread between kids, especially with new variants. But there’s an enormous amount of data that indicates #masks are one of the BEST measures we have to return kids to school w/reduced risk.

6/ Another CDC featured study found — while comparing schools with and without mitigations in same area and adjusting for community rates — that #mask wearing in schools reduced the risks of transmission of COVID-19 by 21%, and cases were reduced by more than a third.

7/ #Ventilation (as easy as open window)+ filtration (HEPA filters to remove 80-90% of particles in room air quickly) can do more to reduce cases than masks as worn by kids with the old varieties of COVID-19. (39% risk reduction versus 21% for masks).

8/ But — hey — what if we COMBINED two of the most highly effective strategies that reduce infection risks since #COVIDIsAirborne. #Masks + #Ventilation could reduce risks by as much as 90% (more in other models).

(Our note: lunch needs to be outside!)

cdc.gov/mmwr/volumes/7…

9/ Also, just putting any machine — like a tiny ionization device in a room — isn’t likely to provide the risk reduction you’d want.

You need masks plus actual True HEPA filters, without gimmicks like “electrostatic,“ etc.

You can even make your own 👇

https://twitter.com/LazarusLong13/status/1417987417928130562?s=20

10/ Fact-based targets are available to help you make an effective plan.

You’ll have to do math, but 700+ engineers endorsed WHO guidelines for ventilation, which specify a MINIMUM of 10 L/s/person of CLEAN air in a classroom for risk reduction.

https://twitter.com/smartrestartaps/status/1366837251179745280?s=20

11/ Our schools are designed for HALF this 10 L/s/p target at 25 people/room as “basis of design.” A large number of classrooms did not meet 5 L/s/p code before APS began working the problem (where they started 👇).
Overcrowd rooms = even less fresh air per student/teacher

11/ Shooting for 10 L/s/person crudely translates to goal of least 5, if not 6 air cleanings of filtered air in class every hour. (More air needed for more people!)
You can check “CADR” on your HEPA (or use TWO MACHINES) and do some math 👇 + #MaskUp!

smartairfilters.com/en/blog/what-i…

12/ A study using a real world classroom came to a similar target. They used #HEPA air cleaners that got to nearly 6 air changes of filtered air, just from the HEPAs, rapidly removing anything from the air in the classrooms they studied. Risk reduced!

tandfonline.com/doi/full/10.10…

13/ Another recent study noted that increasing ventilation, where we have larger numbers of unvaccinated people, could be a useful tool to stop transmission of SARS-Co-V-2. Their classroom target to reduce risks was 7 air changes/hour, or 17 L/s/person.

medrxiv.org/content/10.110…

14/ So #MaskUp, but don’t forget that #ventilation and #filtration are just as important (if not more so) because they actually remove the stuff that’s in the air which can float for hours.

A layered🧀 approach is best with such a dangerous disease.

en.wikipedia.org/wiki/Swiss_che…