And here's a brief synopsis of the data and study Mac referenced, as written by Katelyn Jetelina (author of the newsletter Your Local Epidemiologist):

---
Mask mandates in schools work
What we know: Masks work on an individual level, but the effectiveness of population-level mandates is less understood.

New info: A study from the New England Journal of Medicine compared schools in Massachusetts that kept the mask mandate to schools that removed the mask mandate after the statewide policy was rescinded. Schools that lifted masking had an additional 44.9 COVID-19 cases per 1000 students and staff. (Study can be viewed in full at https://www.nejm.org/doi/full/10.1056/NEJMoa2211029)

Why does this matter? Mask mandates in large settings, like schools, work. This is important to know now or in future pandemics to keep kids in school.
--

On Tue, Jan 10, 2023, 12:40 PM Walker Sloan via Organizers <organizers@lists.sharedweight.net> wrote:

Hey, all you organizers

HARD DATA:

On the issue of masks required OR optional, here is some actually
useful, vaguely understandable data, published by NEJM, New England
Journal of Medicine.  NEJM (Nee-gem) is one of the world premiere
medical journals.

Since I'm interpreting this, my creds are an SB, MIT in physics, and an
engineer in medical devices.  I do numbers.  And I'm on the committee
for the Thursday Night Dance at Scout House in Concord MA.

Attached is a summary sheet for a NEJM article on lifting the mask
mandate in Boston public schools.  My hypothesis -- opinion -- is that a
contra dance is comparable to packing a bunch of kids into a school.
You'll want to view the PDF to see what I'm talking about.

The UPPER RIGHT GRAPH, the important lines are the lower three lines --
two red and one blue.  The red lines are the case rates 2 and 3 weeks
AFTER lifting the mask mandate.  The blue line is the case rate for
schools NOT lifting the mask mandate.  By engineering standards, the two
red lines peak about 50% higher than the blue line.

In the RESULTS paragraph on the left, last sentence: "One third of the
Covid-19 cases that occurred..."  This is another way of expressing a
50% increase.

Do masks PREVENT Covid?  We all know they don't.  Neither do vaxes and
boosters.  What they do is stack the ODDS in favor of individuals and
COMMUNITIES not getting Covid.

I strongly believe that stacking the odds is the responsible way to go.
I do NOT believe in basing policies on surveys of dancer preferences.

Mac Sloan

On 23/01/07 5:56 PM, Laura Alexander wrote:
> Hi Mac,
>
> My understanding of transmission risk is based on information from
> mainstream epidemiologists, not surveys. As a scientist not working in
> epidemiology, I'm curious for expert information and seek it out.
> Believe it or not, I still think our position is appropriate and
> responsible. I'm aware of these studies and the information you shared,
> but thank you for mentioning them. I'm happy to continue this
> conversation offline, but I'd hope you refrain from making assumptions
> in the future about what people understand.
>
> Laura
>
>
>
> On Sat, Jan 7, 2023 at 3:27 PM Walker Sloan <sloan@medevelop.com
> <mailto:sloan@medevelop.com>> wrote:
>
>
>     "Our understanding on transmission risks..."  Surveys reflect
>     preferences, not science.
>
>     Science:  In Nov '22, per the CDC, bivalent boosted people had 1/3rd
>     the
>     chance of testing positive.  This means that requiring bivalent
>     boosters
>     will dramatically cut the number of positives dancing in your hall.
>
>     See attachment.  Light green box at the bottom.
>
>     With XBB.1.5 this number has yet to be determine.  But odds are there
>     will be a good effect.
>
>     Do vaxes prevent Covid?  No, but the odds of Covid producing a bad
>     outcome in vaxed and boosted people go WAY down: Testing positive,
>     transmitting, hospitalization, death -- WAY down.
>
>     Holding dances for unvaxed people not only endangers them, but ALSO the
>     folks they go home to and go to work with.
>
>     Holding unvaxed or vax-optional dances prolongs the pandemic.
>     Regardless of surveys or understandings.
>
>     Mac Sloan
>
>     On 23/01/07 2:07 PM, Laura Alexander wrote:
>      > Arden contra (in Delaware) has a policy that's very similar to
>      > Montelier's, and for the same reasons. We surveyed this fall and
>     dropped
>      > our vaccine requirement, and we'll survey our community again this
>      > month. Without a significant change to our understanding on
>     transmission
>      > risk difference between vaccinated and unvaccinated people, we won't
>      > consider re-excluding unvaccinated people. If it's not safe
>     enough to
>      > dance for community conditions and hospitals, we'll postpone dances.
>      >
>      > Whole policy:
>      >
>      > - vaccines strongly encouraged
>      > - masks required
>      > - hall with excellent ventilation
>      > - contact tracing with mandatory info collection, system run by a
>      > responsible person outside the community, announced at the dance
>     and in
>      > a follow-up email
>      > - announcement that if anyone feels sick after the dance, we
>     expect them
>      > to get tested ASAP
>      > - rapid tests available to those without access
>      >
>      > Thankfully we haven't had any known transmission yet since
>     restarting in
>      > March 2022. We average around 40 attendees per dance.
>      >
>      > I agree with Julian, I hope every local area has a space that's
>      > taking all precautions available, and it also makes sense to me
>     to have
>      > mask-optional dances if there is no foreseeable change to covid risk.
>      >
>      > Thanks for the thread, everyone - it's useful to see what other
>     dances
>      > are doing.
>      > Laura Alexander
>      >
>      > On Sat, Jan 7, 2023 at 12:13 AM Walker Sloan via Organizers
>      > <organizers@lists.sharedweight.net
>     <mailto:organizers@lists.sharedweight.net>
>      > <mailto:organizers@lists.sharedweight.net
>     <mailto:organizers@lists.sharedweight.net>>> wrote:
>      >
>      >     Another pebble in the pond --
>      >
>      >     *  Current booster verified
>      >     *  N95, KN95, KF94 required
>      >     *  Request cases to be reported back to the organizers
>      >     *  Emails collected to report cases anonymously to the community
>      >     *  Max venue ventilation -- cold drafts this time of year in
>     the North
>      >
>      >     NONE of these is sufficient to prevent Covid.  ALL of them
>     help reduce
>      >     transmission.
>      >
>      >     None of us organizers volunteered to be public health
>     officials.  And
>      >     certainly not protocol cops.  But it makes sense for us to
>     STACK THE
>      >     ODDS as high as possible in favor of COMMUNITY health.
>      >
>      >     Maximizing community safety takes precedence over individual
>     preference.
>      >
>      >     That's the most responsible way to organize a dance.  Not
>     just for the
>      >     benefit of our dancers, but also for the greater community in
>     which all
>      >     of our dancers live.
>      >
>      >     Mac Sloan
>      >     Thursday Night Dance, Concord Scout House, MA
>      >
>      >
>      >
>      >
>      >
>      >     Walker Sloan
>      > sloan@medevelop.com <mailto:sloan@medevelop.com>
>     <mailto:sloan@medevelop.com <mailto:sloan@medevelop.com>>
>      >
>      >     On 23/01/06 11:18 PM, Julian Blechner via Organizers wrote:
>      >      > Question for anyone with the "you will alienate someone" or
>      >     "everyone
>      >      > has a different level of risk" mindset:
>      >      > In other areas of life, do you consider someone's personal
>      >     preference
>      >      > (like not wearing a mask) the same as someone's health
>     needs (like
>      >      > having a health condition, or a family member who does)?
>      >      >
>      >      > Like, how is this "both sides have a preference" narrative any
>      >     different
>      >      > from able-bodied people being like "Oh, well, I just don't
>     like
>      >      > handicapped ramps, I prefer steps"?
>      >      > I'm not asking to be mean or rude. I genuinely would love an
>      >     explanation.
>      >      >
>      >      > I think there actually _is_ a way to please most people,
>     and not
>      >     just
>      >      > disregard people with medical conditions (or family with
>     them).
>      >      > That is - making sure no area's dances are all mask-optional.
>      >      > There's a big difference between an area having _some_
>     mask-optional
>      >      > dances, sure, but if they're _all_ mask-optional.
>      >      >
>      >      > Thanks,
>      >      > Julian Blechner
>      >      >
>      >      > On Fri, Jan 6, 2023 at 5:56 PM John and/or Jan Bloom via
>     Organizers
>      >      > <organizers@lists.sharedweight.net
>     <mailto:organizers@lists.sharedweight.net>
>      >     <mailto:organizers@lists.sharedweight.net
>     <mailto:organizers@lists.sharedweight.net>>
>      >      > <mailto:organizers@lists.sharedweight.net
>     <mailto:organizers@lists.sharedweight.net>
>      >     <mailto:organizers@lists.sharedweight.net
>     <mailto:organizers@lists.sharedweight.net>>>> wrote:
>      >      >
>      >      >     As Alan said,  whatever you do you will alienate someone.
>      >      >
>      >      >     What I did with the Brunswick ECD was to ask all of
>     the dancers
>      >      >        - would you dance if masks were required
>      >      >        - would you dance if masks were optional
>      >      >     and so on.
>      >      >
>      >      >     Then I picked the rules that maximized the number of
>     dancers.
>      >      >
>      >      >     I realize that this is harder for Contra, where you
>     have a lot of
>      >      >     dancers that you can't ask, including potential future
>     dancers.
>      >      >     But in my case it seemed like the right way to do it.
>      >      >
>      >      >     John Bloom
>      >      >     _______________________________________________
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