Thread by @sborg40

1.This is the recent article claiming that covid inf gives you 7 times more myocarditis than after covid vax. Totally opposite conclusion than from the big Nordic study. How can this happen? Thread too long but at least the references are there.

frontiersin.org/articles/10.33…

2. Nordic study and comment

https://twitter.com/TracyBethHoeg/status/1517309675015876608

3.The new article is a systematic review and meta-analysis. Such studies raise an alarm bell. Dependent on inclusion of which studies. Starting with 763 studies, ended up with 22 studies,12 studies of myocarditis after vax and 10 studies of myocarditis after covid.

4.Are they of the same quality? No,even the authors admit that 3 of the studies in the latter group had concerns about bias. There was no bias in the vaccine study group papers.

5.Furthermore in the myocarditis postcovid papers one was a CDC/ MMWR study. Any problem with this? Yes. They are not peer reviewed outside the organisation. Should such study, not properly peer reviewed, be included at all?

6.First the biased.China Wuhan early 2020.Retrospective small study .MR imaging of heart in recovering from covid with heart symptoms. Mostly severe covid,all treated with antivirals/antibiotics. Findings they say not typical of myocarditis in many cases
sciencedirect.com/science/articl…

7.Italy early in the pandemic.12 patients(1%)of admitted had myocarditis.Amazing medium age of 78.5 years and most had pre-existing heart disease. Most had serious covid disease and unspecific heart damage common in ITU. Hardly “common” myocarditis.
journals.lww.com/md-journal/Ful…

8.This is a problem. We are interested in young with myocarditis after covid. Most studies very elderly covid pat in ITU care, myocardial injuries common there with sloppy stamped myocarditis diagnosis in the ICD classification. Most studies just accept these codes point blank.

9.Athletes US. Return to play(RTP) screening after having covid.30 screened pathological and further test with MR 3 had picture suggesting myocarditis.
jamanetwork.com/journals/jamac…

10.MMWR article. Retrospective data from US HC provider ICD diagnosis as myocarditis.Authors raise 6 limitations especially as they describe only cases encountered in mostly hospital based system and not all people infected with covid were examined.
cdc.gov/mmwr/volumes/7…

11.All covid complications in an exposure cross over study 70000 patients and looking for many diagnosis apart from covid.
cmaj.ca/content/193/1/…

12.Limitations,covid diagnosis not totally reliable,could affect uncommon associations like myocarditis. Diagnosis relied on ICD. No check if diagnosis was made the same in different HC providers.

13.India. Very small retrospective study 102 patients hospitalised many with pre- existing cardiac morbidities. The three myocarditis cases were probable.
sciencedirect.com/science/articl…

14.China early in the pandemic Wuhan.Retrospective 112 patients severely ill median age 65 years. The 14 myocarditis patients even more, median age 74.The diagnosis on Echocardiograhy and troponin.Mainly elderly ITU patients.
internationaljournalofcardiology.com/article/S0167-…

15.Athlete’s study RTP,1597 athletes screened after covid incl MR. 37 with clinical and subclinical myocarditis only 9 had cardiac symptoms. Limitations that not all infected with covid were investigated (These 2 US athletes studies criticized by others)
jamanetwork.com/journals/jamac…

16.718365 patients with covid infections and a retrospective cohort study, health records from a global health research network.5% developed myocarditits. Were these typical myocarditis?
onlinelibrary.wiley.com/doi/full/10.11…

17.They also had 128939 pneumonia cases pre covid to compare with and had in that cohort 3 .1% myocarditis. Again severity and elderly? Authors conclude, severity of the initial infection was a marker for developing myocarditis.

18.From Israel and is actually primarily a safety of Pfizer vax study in a huge cohort extracting also covid related myocarditis. Matching vaccinated with non vaccinated but non vaccinated could then be vaccinated and matched again with non vaccinated.
nejm.org/doi/10.1056/NE…

19.Contrasts with another Israel study databases used matching records of myocarditis in the population pre covid with myocarditis after covid. They did not find any difference in incidence i.e .myocarditis not more often after covid than background cases.
mdpi.com/2077-0383/11/8…

20.This meta article,the first above must be compared with the big Nordic study 23M. In Hoegs twitter above myocarditis 28x higher in double vaxed than the 13.7/million rate they found post-covid .Even those single vaxed always had more myocarditis than post covid.

21. How can we have two such opposing articles? You can’t compare pears with apples. The only interesting is 15-50 year old how much myocarditis after vax compared to postcovid. Many studies are full of elderly/ITU cases with myocardial damage called covid myocarditis.

22.If there was a clear marked myocarditis risk after covid in the young, these specific studies would have been published after billion cases. It obviously occurs rarely,as seen in published case reports and also after MIS-C but much more seldom than myocarditis after vax.