Probably means exactly that.
If it were mandatory, there is a higher probability he would have gotten it.
You see how that works?
If you really need an exact answer, go get a psychic and see if you can drum the kid up from the dead.
It probably was mandatory. He probably did receive the flu shot. And if he did, it did him absolutely no good whatsoever.
If you really need an exact answer, go get a psychic and see if you can drum the kid up from the dead.
You don't think the father of the kid would know? The one who was the source of this anecdotal evidence?