Juliette Mullin, Senior Editor

The debate on vaccine policies is heating up as a measles outbreak that began at a Disney theme park continues to spread.

Concerned by the effect that pockets of unvaccinated Americans have had on herd immunity, a growing number of doctors are turning away unvaccinated patients. In Arizona, where officials are monitoring more than 1,000 people for measles, a slew of complaints has prompted the state medical board to investigate a doctor promoting an anti-vaccine lifestyle.

Now, the question for public health experts is one we've heard before: Will this be the outbreak that changes our approach to vaccines?