The vaccines themselves and vaccine scheduling change over time. How would we know if something harmful was introduced? Unless of course as you state we are un

The vaccines themselves and vaccine scheduling change over time. How would we know if something harmful was introduced? Unless of course as you state we are unwittingly participating in ad-hoc longitudinal studies. There are any number of `modern` diseases with seemingly unknown causes. It's not a stretch to be skeptical of the safety of modern medicine in general.