It appears that the S protein causes clotting in many people. Aspirin is a blood thinner. So it may have some effect to reduce clotting.

The S protein can cause blockage of capillaries because of clotting, and it is known to damage endothelial cells that line larger blood vessels.

The protein does not affect all people exactly the same way - some people have a possibly genetic-based resistance.

I recommend that you take a baby aspirin daily if you have covid, and if you have been vaxed, definitely take an aspirin daily to ward off side effects.