Vaccination debate flares in GOP presidential race, alarming medical experts

Medical experts reacted with alarm Monday as two top contenders for the Republican presidential nomination appeared to question whether child vaccinations should be mandatory — injecting politics into an emotional issue that has taken on new resonance with a recent outbreak of measles in the United States.

First, New Jersey Gov. Chris Christie, while visiting a vaccine laboratory here, called for “some measure of choice” on whether shots guarding against measles and other diseases should be req