The Nordic data on the frequency of myocarditis after dose 2 of Moderna (Spikevax) in 18-29 year old men have been released: 1/4,800.
For Pfizer, it's 1/25,000.…
>5x difference, but see data from Ontario below (1/5)
Ontario rate is now 1/5600 (mostly Pfizer) in boys 12-17
My ?: Is some of the increase in frequency simply due to awareness of condition? (in addition to increased Moderna use?) 2/5
- Israel rate from NEJM 1/6600 for 16-19 yo (Pfizer)…
(For ref our VAERS pre-print: 1/6200 in 12-15 yo males, 1/10,600 in 16-17 yo (Pfizer))

Reports taken together point to ⬆️ rate in younger boys & after Moderna & ⬆️ awareness of this condition 3/5
I keep saying this, but the question is: how do we minimize harm? One dose in some young males? Accept natural immunity, esp in young males? Decreased dosing? I don't have the answers but I think asking questions is important. 4/5
This condition seems mostly mild but not 100% of the time. Please listen to @drjohnm 's discussion of the severity seen in the recent Israeli papers in @NEJM . The point he makes about these mRNA vaccines being life saving is crucial. 5/5…

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More from @TracyBethHoeg

7 Oct
The Israeli @nejm study published today that stratified for myocarditis rates post vax dose 2 in males age 16-19 found a rate of 1/6600 for Pfizer. Our preprint found a *lower* rate of 1/10,600 for 16-17 yo males. For 12-15 yo males we found 1/6200…
I'm really grateful for this NEJM study⬆️ & glad to see our VAERS-based study didn't provide an overestimate in 16-17 yo males. This was as expected with VAERS typically underreporting. I hope more studies are published with 12-15 year old estimated rates.…
From second NEJM study "Most cases of myocarditis were of mild or intermediate severity" "1 patient had cardiogenic shock, & 1 patient w/preexisting cardiac disease died of an unknown cause after.. discharge Left ventricular dysfunction in 29% of patients"…
Read 6 tweets
25 Sep
MMWR AZ 🌵 mask study #1 limitation:
-Not adjusting for community cases in Maricopa Co (R) rising more during the study (see Figures)
-They adjusted for pre-study case rates, but that was not enough
-remember ~ 95% of school cases come from the community!… Image
Maricopa also had a lower vaccination rates: 47.6% vs 59.2% in Pima.

Likely the entire story here is more school cases in schools w/o mask mandates (mostly in Maricopa) due to higher comm. case rates related to lower vax rates. How did this become a mask story?🤔
Since I am literally sitting on the side of a soccer field in Stockton, for further info, I want to refer you to @VPrasadMDMPH 's discussion of these two MMWR studies & why we unfortunately can't learn about the effectiveness of masks from them.…
Read 4 tweets
12 Sep
I want to answer 2 questions we are frequently receiving about our study (which are excellent questions!):
1. Why did you use 120-day COVID hospitalization risk rather than overall COVID hospitalization risk?
2. But isn't post COVID myo *more* common than post-vax myo? 1/
2/ The US infection-hospitalization risk in the peds population is too uncertain bc we don't have reliable seroprevalence numbers. Based on a v recent analysis of UK data there is about a 1/750 chance for a child to be hospitalized/infection. TY @apsmunro
3/ We used 120-day hospitalization/population (just as the CDC did in their analysis) because there was less uncertainty about its accuracy. It also allowed us to include multiple rates in our model & incl. recent delta rates, as shown below from COVID-NET…
Read 12 tweets
10 Sep
It's important to note, it's the CDC's estimates of myocarditis in boys & young men that have been the outliers. Israel & Canada reporting similar rates of post-vax myo to the 1/6,000 from our study. TY @_lewisy for the Israeli data ⬇️…
And rates from Moderna may be significantly higher:

And those Moderna rates are predicted to be even higher in the 12-17 year old boys:

Read 4 tweets
9 Sep
Our group's analysis of pediatric post-vax myocarditis rates stratified by age, sex & dose. An extensive harm-benefit analysis is included w/consideration of presence or absence of comorbidities

Thanks @drjohnm @KrugAlli & @ifihadastick for the teamwork…
"For boys 12-17 without medical comorbidities, the likelihood of post vax dose 2 CAE is 162.2 & 94.0/million respectively. This... exceeds their expected 120-day COVID-19 hospitalization rate at both moderate (August 21, 2021 rates) & high COVID-19 hospitalization incidence"
I agree with @DrJBhattacharya highlighting @adamhfinn of JCVI here stating how cautious we need to be with our vaccination recommenations in this low risk group

Personal bias: I am a mom of 10 and 13 year old boys & want the best for them & all kids

Read 6 tweets
2 Sep
Nice depiction in @Forbes showing COVID in schools vs. from schools vs in the community as observed in Wood, Co, WI. As senior author of this study, it was tempting for me to believe this pattern was contingent on masking kids, but for many reasons I have come to doubt this 🧵:
First, around 8% of the kids in the study were not compliant with masking. Second, kids ate lunch indoors (unmasked, of course). Third, the Scandinavian experience has been similar to Wood Co where school spread minimal but kids unmasked (…).
Fourth, as my son says "Mom, kids just take off their masks when the teachers aren't looking." [aka child compliance].
Read 7 tweets

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