Disagree on the recommendation not to push masking for currently healthy children as this blatantly disregards the risks of Long COVID resulting in no longer healthy children. Particulalry when you corrently point out how little states have done to address indoor air quality in schools (which would benefit much more than just COVID/other airborne illnesses, to include allergens and overall cognitive function once CO2 levels are lowered to healthy levels). Disappointing to say the least.

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The very different NYC hospitalization rates for unvaccinated adults vs vaccinated adults are still shocking to me - vaccination STILL making a big difference.

Very interesting about home air filters becoming 95% less effective due to charged wildfire particles. Amazing how much of the smaller particle/virus filtration may be electrostatic versus mechanical apparently.

And finally, I am bracing myself for disappointment regarding the CDC meeting. In an interview with PBS, Dr. Offit (whom I respect greatly) stated that he believes the new boosters should only be recommended for 75 yo and up:


As an FDA advisor, he has a lot of influence and expertise...

Yet the game is not just reducing risk of hospitalization and death, but also reducing long Covid burden and disability, community spread, and boosting some modicum of herd immunity, even if temporarily through the anticipated peak Dr. Jetelina is talking about this December perhaps.

I don't think there is enough data out there to definitively determine whether boosters reduce long Covid, but just because enough studies haven't been done doesn't mean we can't take a small intuitive leap of faith?

Vaccination absolutely reduces long Covid risk, perhaps around 40% reduction according to this meta-analysis:


The same analysis showed up to 20% of people already experiencing long Covid reported improvement in symptoms after a booster.

Maybe I'll find time to leave public comment about this for the CDC meeting, but if anyone else has a similar (and more evidence based!) assessment regarding boosters and long Covid, please advise or leave a public comment by tomorrow. Any known studies on this would be greatly appreciated.


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Sep 7Liked by Katelyn Jetelina

Another incredible helpful post! Might you think about doing one on how to manage return to school/work after having COVID or being exposed? It seems like it's time for an update. Should we be "testing" negative prior to return or 5 days out with another 5 masked still holds? Thank you!

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Dr. Jetelina... As always, I appreciate the clear, direct, informed, pertinent message. Today, I'm thinking and thanking for the shouting about ventilation.

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‘Political inertia’ is one way to put it. Pardon that I’m not as gentle as you, KJ, but I texted POTUS last evening and suggested he pull up his big boy pants. :)

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"In one of the best mask studies I’ve seen, school mask mandates also reduced transmission and absences."


This was a terrible study, and I politely pointed out the reasons why last year.

Quick review of criticisms of "EpiEllie" NEJM Study:

1) The authors had organized and promoted a Change.org petition to get Boston to re-instate mask mandates before this was published.[1] Was there any doubt that the authors were NOT going to use the weakness of observational studies to show them what they wanted? They fail to mention this in disclosures, as well as their previous OpEds begging for masks to come back [1]. The authors entered this paper with clear bias. The same reason I would be skeptical of a paper by Peter McCullough claiming to find Ivermectin beneficial, I am skeptical of a paper written by EpiEllie and her pro-child-mask colleagues.

2) The authors included schools in their "mask group" which had actually received mask-waivers, demonstrating they were not thorough in data collection - only thorough enough to give the result they clearly wanted. [2] This warrants retraction.

3) They claim in the discussion that the testing differences didn't matter between masked and non-masked schools, but you can see in the supplement that this is clearly false. This should be disqualifying [3]

4) Obvious Data Dredging - look at how high cases were in both cohorts back when everyone was masking. The chart cuts off the "before", but that is a relevant metric as it removes potential seasonality conflicts. And the obvious question - why were cases so high when all districts were masking? (I know the answer - we retreat to the "Swiss Cheese" excuse anytime cases are high and everyone is masking)

5) Logically this makes no sense. The remaining people today that cling to the mask hypothesis have now said cloth masks don't work, surgical masks barely work, what we need is "fit tested n95s with no gaps". Yet this study claims that loose fititng cloth masks (which is what these kids wore) made some massive difference. That is ridiculous and has been falsified by RCT already.

You have a large audience and are passing along nonsense like this without being critical. Why not employ the same rigor assessing this study as you did in the DANMASK study? [4] DANMASK didn't find benefit of community masking, and you had a lengthy post picking apart the study. Yet repeatedly, I see you promote much weaker studies without skepticism, and as a result, you are sliding into superstition.


"Science invites us to let the facts in, even when they don’t conform to our preconceptions. It counsels us to carry alternative hypotheses in our heads and see which best fit the facts. It urges on us a delicate balance between no-holds-barred openness to new ideas, however heretical, and the most rigorous skeptical scrutiny of everything-new ideas and established wisdom….. When we are self-indulgent and uncritical, when we confuse hope and facts, we slide into pseudoscience and superstition."


[1] https://twitter.com/EpiEllie/status/1429102872470433795


[2] For example, here are schools announcing exemption which are included in the "mask cohort" of the study (11 districts in total had exemptions the authors appeared to be unaware of)



[3] Search for this phrase in supplemental documents:

“ …the following close contacts are exempt from testing and"


[4] https://www.facebook.com/permalink.php?story_fbid=pfbid01SraZhfgd3fvJ969SrsjufxCuWE92DJRTW8dXbYqMFemjX5WYVUwD85GPJbMFVQyl&id=101805971467321

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Hi Dr. Jetelina, I am not sure how best to ask you a question that is not on the current topic, but here goes: Are you comfortable with anyone over 65 (?) getting the RSV vaccine, without consulting their provider? I know that in earlier posts you have noted side effects and were waiting on more data. I have not been able to find an update on your thinking. Thanks!

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I desperately hope they allow covid vaccines for all. My 15 year old has been vaccinated with all available, just waiting for the new, but has gotten covid twice. She starts cosmetology school next week.

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My youngest (age 9) is absolutely terrified of needles. It was a huge struggle to get him to sit still for his covid booster. I want to save that fight for covid, so how is the effectiveness of the flu mist nose spray vaccine?

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It’s great to know that flu shot protection wanes less quickly for kids, so even though flu won’t likely peak until end of November, it makes sense for kids to get their flu shots now. This frees up appointments in October and November for the older crowd seeking vaccines closer to the holidays.

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It seems antigen tests are failing to identify Covid until several days into symptoms for people I know this past couple of months. Is there anything to make them more accurate earlier? Are the new variants just not showing up?

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Can you comment on risk of mycarditis after COVID-19 vaccination for adolescent males?

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So helpful thank you!

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How much increased protection does a (good) mask afford an individual in a situation where others are unmasked? I'm hearing a lot of arguments that "we don't need to require masks at X event because if you want to mask, you're basically just as safe as if everyone masked" and I would love to know what the actual research on this (if there is any) shows at this point. Thanks.

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YLE - can you comment on your understanding and interpretation of the significance of the recent Cochrane article reviewing studies on masking and handwashing for control of respiratory viral illnesses?

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Thank you so much for another very informative news letter. It's wonderful to have a place to go to get the most updated correct information. I'm very interested in what comes out about the new Covid vaccine as I am a compromised senior citizen.

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