As someone who's about to become a parent (on the order of weeks now), this drives me up a fucking wall.

My instinct is generally towards politeness[0] so it goes against my nature to get up in people's faces. But I'm wondering if I need to take a hard line on vaccination when it comes to who I allow to spend time with my kid.

[0]: See http://www.math.uh.edu/~tomforde/hquotes.html, the quote on p247.