The CDC reports diseases like whooping cough and measles are making a comeback. Many doctors point to the declining number of vaccinated children as a cause for the rise in disease.
As we reported Tuesday, San Luis Obispo County has more than double the rate of unvaccinated kindergartners than the state average. The parents opted out because of personal beliefs. It could be religious beliefs or more commonly, the belief that vaccines are not safe.
More than a decade ago a now discredited study was published by Andrew Wakefield linking autism and MMR, the measles, mumps, rubella vaccine.
"Because of one really corrupt physician 15 years ago, who did a really bad study, you know, people believe it," said Pediatrician, Dr. Natasha Raja.
Wakefield was stripped of his medical license, but the vaccine/autism scare still persists - and a major reason why some parents won't vaccinate. Shane Ellison has a masters in organic chemistry, author of the book "Over the Counter Natural Cures", and the father of three unvaccinated children.
"If you look at the vaccine package insert, and you look at the warnings, autism is one of the top warnings, because it's happening so frequently," said Ellison.
But Dr. Penny Borenstein, San Luis Obispo County Public Health Officer, has a child with autism - and has a firm belief based on multiple, creditable studies - there is no link.
"There is something or some things that are causing the rise and the rates of autism. But to determine that it is based on vaccinations is an unhealthy phenomenon that is going on in our community," said Dr. Borenstein.
Shane along with other parents who don't vaccinate are also worried about what's in vaccines.
"When you do vaccinate you're looking at being exposed to different kinds of toxins and side effects that can't be reversed," said Ellison.
We took a look at what's in vaccines. The CDC says there are preservatives in safe amounts, used to keep bacteria out and improve the effectiveness of vaccines. Aluminum is one of them. It's in the air we breathe, the food we eat, and water we drink.
"There's more aluminum inbreast milkk than all of your childhood vaccines put together," said Dr. Raja.
Even when injected, multiple studies found, aluminum in vaccines doesn't show up in a baby's blood stream.
Thimerosol, an inactive compound of mercury was taken out of nearly all childhood vaccines more than ten years ago... out of fear of autism... but again no proof.
"You get more mercury out of a piece of fish," said Dr. Raja.
Multiple studies show, autism continues to rise, despite the removal of thimerisol.
Then there's formaldehyde. Its produced naturally in the body. The FDA says the amount of formaldehyde already in babies is 50-70 times higher than the they could receive from a single dose of a vaccine or from vaccines administered over time.
"In my 13 years as a hospitalist, I never once saw a child with a life threatening illness, with anything that required hospitalization because of a vaccine, anything that was permanent damage," said Dr. Raja.
And with the increasing number of parents opting out of vaccines, are children now at risk for disease? Dr. Raja says yes because of a potential breakdown in herd immunity.
"Our vaccination rates are about 85 percent and in order to have herd immunity that means the number of people who are vaccinating their children are therefore protecting your child - you need to have vaccination rates well over 90 percent."
And health officials say, it's the children who cannot be vaccinated because of a medical condition, or pre-vaccinated babies who are now most vulnerable.
"Those are that babies that die, and it is the most helpless feeling," said Dr. Raja.
While millions of vaccines are safely given yearly, the CDC says no vaccine is 100 percent safe and effective. differences in the way individual immune systems react account for extremely rare occasions when patients experience side effects.
The best advice, do your research - but check the sources.
When parents surf the internet they often run across studies that look credible, but sadly are not.
the CDC, FDA, and American Academy of Pediatrics are all great places to get information... as well as your child's pediatrician.