But do we know for sure that the measles outbreaks and reluctance to vaccinate result from their influence?

In recent years measles outbreaks have been rare.

But what they could see was that, sooner or later, the drop in vaccinations would lead to measles outbreaks.

In part because of the recent measles outbreaks, however, there has been a move in many states to limit or eliminate the ability to 'opt out'; of vaccinations.

Perhaps in part as a result of this downturn there had been a substantial rise in the number and severity of measles outbreaks.