Thread by @han_francis

This thread is intended as a "mini literature review" on arrhythmias after COVID vaccine versus COVID - there are people claiming that heart block is a serious, worldwide risk after COVID immunization. Lets see what the actual research says.
#COVID19 #mRNA #VaccinesWork

There are in general fast heart rhythms and slow ones - the technical words are tachyarrhythmia and bradyarrhythmia. Both can cause dizziness and sometimes life threatening problems, but lets go through them systematically, using only peer reviewed literature to think through.

TLDR#1: In contrast to the myocarditis risk being skewed towards old boys/ young men, the risk difference of having an arrhythmia after COVID is much worse, than that equivalent risk after COVID vaccine and this risk persists at all ages.

TLDR#2: It is possible to be empathetic to those who experienced an adverse event after 💉 that was a heart rhythm problem, while refraining from misrepresenting the research to them. Don't listen to those who extract maximum possible fear from myocarditis.@VPrasadMDMPH

Now, the details. The heart rhythm system is a bunch of specialized cells that are buried in the heart muscle which control the muscle cells by delivering electricity (the same flavor as the one in your house just a lot lot tinier).

We measure the electricity by a thing called an EKG, which is basically a fancy medical voltmeter but much, much more sensitive (to pick up tiny voltages).

Electricity is normally invisible to the unaided eye but if you could put on magic goggles it would look something like this (this video is actually filming calcium ions moving around) . youtube.com/shorts/zdBgxIp…

The reason slow heart rhythms can occasionally be problematic is because if you are missing heartbeats enough of the time, they can make you pass out (in the most severe circumstances). Blood flow can also be disrupted if the heart moves too fast (atrial fibrillation/ flutter).

I am happy to acknowledge the existence of case studies of serious slow heart rhythms after COVID vaccination, but to actually determine a rate, epidemiological studies are needed. The most helpful study is the one done by @UniofOxford on population level rates of arrhythmias.

The main article focuses on myocarditis but it also does have a very nicely done section in the supplemental tables focusing on the types of arrhythmias observed pubmed.ncbi.nlm.nih.gov/34907393/ .

Point 1: The total rate of arrhythmia across the whole population studied is unambiguously higher after COVID illness (bottom row) than the risk after vaccination with either the Pfizer or Moderna or ChAdOx1 vaccines (upper rows).

Point 2: Those who hype vaccine myocarditis love to leave out table 4 in figure 2 - which shows the risk of all cause arrhythmias after COVID diagnosis is much higher than that same risk after immunization. They like to emphasize the first 3 but not #4.

Point 3: We can see what those actual arrhythmias are; they consist of both the slow and the fast. Here's a table with some key data points from the supplemental tables:

The accompanying table shows the risk associated with heart blocks (the heart blocks are divided into smaller time periods). The risk of slow heart rhythm spikes early after your COVID infection and gradually goes down, but is larger than than same risk with immunizations.

Even in those people < 40 years of age, the risk of arrhythmia in COVID disease exceeds the arrhythmia risk in COVID vaccination. The risk difference according to this really well done paper is not subtle. A legit further direction of research...

is to see if the risk of arrhythmia is different with Omicron variants (meaning did the risk of COVID arrhythmia change over time from 2020-2023); studies on this question are sparse.