Stewart (together with his staff of writers and researchers, of course) is a national treasure.
Meanwhile, the website Talking Points Memo reports (link) that legislators in California have introduced a bill to protect more children from well-meaning but ill-informed parents by limiting exceptions to school vaccination requirements to those based on legitimate medical reasons and (less justifiably) religious beliefs.
(Update: Apparently the bill is to eliminate all exceptions except for medical reasons, which I believe is the practice in most states now. The vaccination requirement does not extend to home-schooled children.)
(Second update: I keep reading inconsistent things about whether the California bill would eliminate religious as well as other non-medical exceptions, but it appears that the great majority states currently do allow religious exemptions that in actual practice amount to a general right for parents to opt out. In fact, among organized religions, only Christian Scientists oppose vaccination as a matter of doctrine. Some subsets of the Amish may do so as well, but that's unclear. I'll try to have further information on this in a later post.)
In the meantime, astronomer and science writer Phil Plait argues (link) that insulting anti-vaccine fanatics makes it even less likely they'll change their minds. That's a valid point, and one that far too many of us on line tend to forget. But I'm not sure those folks are very persuadable to start with, and maybe we should be more concerned about the people who don't know which side to believe. Treating anti-vaccine types too respectfully risks giving the impression that their claims are scientifically reasonable, and the fact is they're simply not (as Plait clearly recognizes).