Health officials around our country worry about risks from an increase in parents who won't sign permission forms to let elementary-age kids be vaccinated against preventable childhood diseases such as measles, mumps, chicken pox and whooping cough. More than half the states report at least a slight rise in the rate of exemptions since 2006. Some parents feel shots have side effects, other risks or are unneeded.

The number of shots worries some moms and dads. From infancy to age 6, most youngsters are stuck with a needle about two dozen times. The effect over time of all those shots has not been studied enough, objectors say. Actually, few serious problems have turned up over years of vaccinations. Several studies have shown no link with autism, a 1990s concern that has been widely discredited.

Skipping shots that bring immunity (protection) against disease can have an impact beyond individual families, specialists warn. If an outbreak begins among children whose parent opted out, a vaccinated child could be at risk because no shot is totally effective in everyone. For example, two northern Indiana communities had chicken pox outbreaks among children in late November. Middlebury Community Schools in Elkhart, Ind., recorded at least 13 cases over two weeks and health officials directed parents to keep more than 50 unprotected students home for three weeks as a precaution. "The time to stop it is now, not drag it out," explained Dr. Daniel Nafziger, a county health official.

Opt-out mom says: "Many of the vaccines are unnecessary and public health officials don't honestly know what the effect of giving so many vaccines to such small children really are." -- Jennifer Margulis, parenting author in Ashland, Ore., who has four kids

Nurse says: "Many parents have grown up not being aware or seeing some of these diseases, and what effects they have on children. We have seen diseases reappear. We've had chicken pox come back. Europe is dealing with measles right now." -- Leslie Miller, public health nurse, Harrisonburg, W.Va.

Doctor says: "An overwhelming growing body of scientific evidence shows that there’s no link between vaccinations and autism. I think there’s been a lot of misinformation on the Internet, through the media, that’s put a lot of fear into parents." -- Dr. Alana Levine, pediatrician in Tappan, N.Y.