Oregon's legislature spent part of last year working on a bill that would end non-medical exemptions from vaccines for children. In the end, the House passed the bill, but it was withdrawn in the Senate, part of the deal to bring the Republicans back from a walkout.
The story across the state line is a bit different: California passed a bill ending non-medical exemptions in 2016.
And research after the fact shows the law had the desired effect, boosting vaccination rates up to "herd immunity" levels.
Peter Hotez at Baylor University co-authored the study; he joins us with highlights.