It isn't just young children at risk. Some fraction of the people who were immunized are still at risk of catching the disease. Getting an immunization doesn't

It isn't just young children at risk. Some fraction of the people who were immunized are still at risk of catching the disease. Getting an immunization doesn't guarantee immunity. There is a fundamental trade-off at play: make the immunization shot too strong and more people get harmed; make it too weak and fewer people actually get immunity. The funny thing about the anti-vax crowd is they have opted to turn the dial to the maximum, and most dangerous, setting: use a full strength virus in order to gain future immunity.