Thread by @abledoc

Here is a thread on what people with heart disease should consider before taking vaccine 1/n
People with heart disease are at increased risk from COVID19 not only due to heart disease but also from diabetes & hypertension. Thus benefits of vaccination are greater. Now the nuance

https://twitter.com/serioustaurean/status/1352473379467534337

Reports of sudden deaths following vaccination have received widespread coverage, mostly in the old (Norway) as well as young (Karnataka, India & Portugal) attributed to Cardiac events. This has to be seen against millions vaccinated. Risk of COVID19 death above 70 is 14% 2/n

One can say a particular mode of death is attributable (partially or fully) to vaccination if it is raised above the baseline risk. Even still benefits of vaccine outweighs risk.
Let's discuss whether vaccine can plausibly trigger cardiac events in high risk individuals 3/n

Phase III Trials can still miss rare adverse events as Trials are typically conducted in healthy populations making it necessary to have surveillance in place during large scale vaccine roll-out. Creating a registry of subjects before administration of vaccine helps with baseline

Vehicular & Urban pollution spikes have been linked to spikes in myocardial infarctions & strokes.
Low grade systemic inflammation (which vaccines can also induce) tilting the balance towards blood clotting is the culprit here 4/n
This is a threshold effect, like an avalanche

Bacterial sepsis (Moradabad incident of pneumonia pt) also makes blood more likely to clot. This is exemplified in catastrophic antiphospholipid syndrome (thrombotic storm) where infection and/or inflammation triggers clots in multiple sites. 5/n

Vaccine could be potentially the trigger that pushes the avalanche across the threshold. Avalanche was inevitable, but it just happened now, perhaps a little earlier.

Now, what about patients taking treatment for heart disease such as Aspirin and statins or BP medicines.
These drugs actually reduces risk of blood clots and heart attacks compared to someone with unknown, ongoing or smouldering heart disease. 6/n

Now if you have symptoms of ongoing heart disease (chest pain or discomfort) or infection (eg fever), even a viral infection, postpone your vaccination until you are treated.
Ongoing infections can also make vaccines ineffective besides increasing risk 7/n

These mechanisms are possible only in people with underlying cardiovascular disease. Can the virus and vaccine do anything directly. Coronavirus can affect blood vessels and can persist in blood vessels for weeks (longer in immune deficient) after throat swabs are negative. 8/n

If you have persistent (rare) presence of virus inside your body, vaccine induced immunity can produce immune reconstitition phenomena which may look like autoimmunity or vasculitis but it would likely take at least a week Early (<48 hrs) events are unlikely to be due to this 9/n

Hence if you have an ongoing COVID19 infection or recently recovered, it would be safer to wait for a few months to wait for the virus to clear naturally before taking vaccines. 10/n (This advise could change if and when potent antivirals may become available.