Quote Originally Posted by schigh View Post
Actually, for measles, vaccination within 72 hours of exposure may provide protection. And it can be difficult to know exactly who was exposed in some settings. Vaccination will protect you from further exposures as this outbreak continues if you didn't get disease in the earlier rounds. And those kids they do let back in school after vaccination are supposed to be followed and excluded immediately if they develop symptoms (and not wait for rash). This policy has not caused problems to date in the post elimination era in the US. The problem is when contact tracing, isolation, vaccination, and monitoring for symptoms is not done efficiently and the longer an outbreak goes on the more difficult it is to do this. The key to outbreak control for measles is early intervention and that seems to have been lacking back in September/October.
And realize the kids being vaccinated and returned to school are going to a setting where the other kids are vaccinated, not staying out of school and congregating with a group of kids who are not vaccinated where they will efficiently transmit virus if they were infected.