(DURHAM) -- More parents are opting out of school shots for their kids. In eight states now, more than 1 in 20 public school kindergarteners aren't getting all the vaccines required for attendance. Duke physician and researcher Dr. Sam Katz says those statistics are unsettling.

"Most young parents today and young physicians and young nurses have never seen cases of polio, of measles, of diphtheria, of whooping cough. The fact that we don't have these in this country today except in rare instances is a testimony to the success of the vaccine programs," he says.

Dr. Katz says making sure your child has been given proper vaccines could mean the difference between a healthy life and death. Dr. Katz is one of the researchers who developed the measles vaccine.