Thread by @ChecchiaPaul

1/ Today, I was going to examine the myth of fertility effects of the vaccine; but then Israel reported a “probable” link of vaccination to myocarditis so change of plans.

2/ Let’s revisit the entire entity of cardiac findings post vaccination as well as what COVID does to the heart.

I had written about how the inflammatory response following vaccination may be the culprit in the rare cardiac findings being observed.

3/ I still stand by that hypothesis. I don’t see any new data or evidence that would persuade me from thinking that the heart is a bystander to the cytokines and inflammatory mediators generated by the robust immune response of these fantastic vaccines.

4/ These reports remain relatively rare, mild, and fully recoverable. However, there are lessons to be learned and potential avenues to take that would minimize even these incidents.

Let’s look at the Israeli reports in detail.

5/ I would like to both applaud their healthcare system for being able to capture this data; but I would also like to caution that this is all data via a news report rather than evidence that withstands the peer-review process. That said, it remains important.

6/ What they are now reporting is that there is low incidence of myocarditis if you look at all individuals vaccinated; but higher if you restrict to ages 16-24 and the male gender.

7/ Additionally, and I think most importantly, they report that 95/110 or 86% of these cases occurred after the 2nd dose of the Pfizer vaccine.

8/ (this will be important later) Finally, they are investigating 2 deaths that are not counted in those numbers with one being “unlikely” tied and the other with very little data available. All others recovered fully. It is unclear how many, if any, were treated and with what.

9/ (Again, needs real scientific review rather than news reports)

Full disclosure, my son fits squarely in that age range. He received 2 doses of Pfizer. I would have him do it again. I wasn’t worried.

What I remain worried about is actual COVID, not the vaccines.

10/ I feel the need to highlight yet again the devastation that full-blown COVID can do to a heart. (jamanetwork.com/journals/jama/… )This is a fantastic and easy to read summary of what we know about COVID and the heart.

11/ I would like to highlight that the cardiac injury we see appears to be mediated by uncontrolled inflammation rather than direct attack of the virus on the heart (viral myocarditis).

12/ This is extremely relevant to the discussion about the response from vaccines because one of these cascades is out of control, while the other is limited. Let me explain.

13/ When an unvaccinated person gets infected with SARS-CoV-2, the virus not only triggers a massive inflammatory and complement activation response; but it also continues to replicate unchecked.

14/ This isn’t the spike protein replicating and doing damage, it is the entire virus taking over one cell after another, using it to make more virus, destroying the cell in the process, and feeding gasoline into an already burning fire in the body.

15/ The inflammatory response that is seen is out of control and overwhelming. (think 9 or 10 out of a scale of 10!) It is also a never-ending forward feeding loop as more virus leads to more inflammation.

16/ As I’ve written about previously, the heart is so damaged by some of that response that some people are unable to recover from that massive systemic inflammatory response and it serves as the cause of death.

17/ Now, in the vaccinated person, the virus simply can’t get a hold of any cells because the antibodies generated by the vaccine stop it in its tracks. No foothold in the body.

18/ When the vaccine triggers its initial immune response, some of the byproducts are the same as those in the response above (stuff like cytokines and interleukins).

19/ Therefore, it is not surprising that some of the same type of inflammation occurs (you feel tired, febrile, achy). Here is the difference. Because the mRNA falls apart after doing its initial job, that inflammation is self-limited, controlled, and smaller.

20/ There is no actual virus to continue to feed the fire. That is the power of “priming” the immune system in a regulated manner. (think 2-3 out of 10 and can never go higher than that!)

21/ This in no way means that we should not try to understand why some of these young men seem to have more of cardiac response than others. Maybe they would be the mortalities of an actual COVID infection if they remained unvaccinated?

22/ Their immune systems may hold the key to treatments in the future. Additionally, there is an emerging body of evidence that would suggest that younger people should delay the second dose of the vaccine. (timesofisrael.com/to-beat-side-e…) This is not unreasonable.

23/ This also doesn’t “fly in the face of the science.” Yes, the initial studies were done with a 3- or 4-week interval, but let’s be clear that those times were picked to be an expediated standard (we had never done this before).

24/ Also, the fact that the trial reports 52% efficacy after the first dose is a bit misleading. (nejm.org/doi/full/10.10…) As this great letter in the NEJM points out if you take away the very first 2-week block after the 1st dose; the efficacy is 92%.

25/ This approach is not at all crazy and is being advocated by many people way smarter than me. (nature.com/articles/d4158…) (academic.oup.com/cid/advance-ar…)

So, is it reasonable for a parent of a teenage boy to delay the second Pfizer or Moderna dose?