for more dr. cory aber. what is your professional conclusion? is there risk in vaccines to the level where it has -- people have to be concerned about it being mandatory? >> well honestly, after doing research for the last 20 years in this field, at this point there are no scientifically-based studies to say that there is anymore risk in vaccination that would cause you to not want to vaccinate your child because of the risks of the actual diseases that are out there in the united states right now. for example, we're talking about the measles vaccine. measles vaccine is very important. but in california we also had a measles outbreak. we also had a meningitis outbreak. we also had a pertussis outbreak. and let's be very clear here.