It is common for most vaccines, that a person will become ill for a short time after receiving that vaccination.

But when a person receives a flu shot, we know they become sick with a mild case of the flu. At least that is how I understand this.

In the case of the Mrna shots, you are not being injected with a milder or dead version of the Covid virus.

So in this case, what exactly is it that people become sick with for a few days after receiving the "jab"?