Well, it used to be that infant mortality was a lot bigger, some of which was probably infants dying to things they were exposed to. So we can't just ignore su

Well, it used to be that infant mortality was a lot bigger, some of which was probably infants dying to things they were exposed to. So we can't just ignore survivorship bias in considering these things. In general, we're probably better off with controlled, safe exposures (e.g. vaccines) than uncontrolled exposure and simply hoping we'll survive anything we catch.