It doesn’t happen immediately – as on the spot. It can happen 24 hrs later. I personally know a family in Jerusalem who have a 20 yr old (approx) child in permanent vegatitive state. That child was a beautiful lively boy – until he was vaxxed. Not too long after they got home he started having seizures, and he slowly deteriorated till by the time was about 10, he was hospitalized full-time.
Seeing something like that is a very quick and simple way to have the greatest fear of those vaxxes.
And for the idiot who asked: why doesn’t it happen to everybody? The researchers (even pro-vaxx) recognize that there can be a genetic predispostion – just no one has bothered to invest in trying to discover what that could be.