In my case it wasn't that I knew, I just was ready to die instead of suffering something worse with the not long term tested vaccine, and yes for me there are ailments far worse than death

It helped that I caught covid 1.0 before there were any vaccines, it was pretty bad but I survived it and had no pain in my lungs after 2 months

But I told my family, yet I did not want to be responsible for if they did not survive COVID, so I told them that ultimately they must make that choice but that I would never take it