The lede:

Measles are coming back. The Centers for Disease Control and Prevention reported that measles outbreaks have reached a peak not seen since 1996. By late August, 131 cases had been confirmed in 16 states.

Almost half of the cases occurred in children who had not been vaccinated because their parents claimed religious or personal exemptions to vaccine mandates.

“This measles outbreak may be a warning shot,” said Paul A. Offit, MD, chief of the infectious diseases division at the Children’s Hospital of Philadelphia. “We now have communities that have a lack of herd immunity. That puts children at risk.”

Other physicians and public health experts are echoing Dr. Offit’s concern. They say states are making it too easy for parents to exempt their children from the vaccines required for school entry. As scientifically unfounded information about vaccine risks swirls around the Internet and among parents, experts say the exemption rate is bound to grow.

But others worry that toughening the opt-out process, or just talking about mandates, could lead to an even greater loss of public trust in the immunization system.

The whole shebang.