Holly Richards | Coshocton Tribune

To this day, Kim Markley still wonders how one of her perfectly healthy children became an epileptic virtually overnight.

When he was a year old, Markley's son Skylar received the recommended MMR (measles, mumps, rubella) shot. A week later he started having severe, full-blown seizures.

"It's a weird thing; he was healthy, then this happened," said Markley of Coshocton. "The doctors said the seizures could have been from the vaccination, but they're not sure. He has epilepsy now and has been on medication since he was three."

The incident happened seven years ago, but her memories have been stirred up with the notion of the link between vaccines and autism or other disorders.

"It probably could happen," Markley said. "I've only heard of it happening, but never saw any proof. You just have to take your chances."

Scientific evidence, however, does not support the supposed connection. According to an Associated Press report on Feb. 12, a special federal court turned down families in three cases who argued that a combination of the MMR vaccines and other shots triggered autism.

The same has also been reported by the Centers for Disease Control and Prevention.

"The medical and scientific communities have carefully and thoroughly reviewed the evidence concerning the vaccine-autism theory and have found no association between vaccines and autism," the CDC Web site stated.

The Associated Press and Ohio Department of Health also reported that the number of religious and philosophical exemptions for vaccines nearly quadrupled in Ohio from 335 (0.2 percent) in 1998 to 1,186 (0.8 percent) in 2008. This figure represents fewer than one in 100 children.

While numerous vaccination's are available and requirements vary from state to state, DTP (diphtheria, tetanus, pertussis), Hepatitis B, polio, and two doses of MMR and varicella (or chicken pox) are necessary before children enter kindergarten in Ohio, said Dr. Vicki Whitacre, medical director with the Zanesville-Muskingum County Health Department.

"Being in public health, I'm 100 percent committed to encouraging people to get vaccinated," said Bob Brems, health commissioner with the Coshocton County Health Department. "It's a successful medical treatment, and the reason why small pox was eliminated from the face of the Earth. The benefits outweigh the negatives."

Even after her family's unfortunate incident, Markley is not against vaccination's. Skylar, now eight, still gets the recommended shots; Markley said he was fine when he received his last dose before entering kindergarten.

She also has three other children - all boys, ages seven, five and two - whom she makes sure receives the required immunizations, just at different times.

"Since my doctor saw Skylar's reaction, she's taking precautions with my other kids and waiting longer," she said. "Instead of giving them shots at 12 months old, she's giving them at 18 months. I think it's made a difference; by waiting six months, they were fine. I'm OK with vaccination's, but maybe they're given too soon. Maybe it was a bad dose (that Skylar got). My mom talked to someone at Marilyn's Natural Foods, and they said maybe it was mixed with mercury."

The CDC reports that thimerosal, a mercury-containing preservative, has been used in some vaccines and other products since the 1930s. While there is no concrete evidence of significant harm in low doses, several agencies suggested thimerosal be reduced or eliminated in vaccines as a precaution in 1999. Since 2001, thimerosal is no longer used as a preservative in routinely recommended childhood vaccines, except in some flu shots, the CDC said.

"We're learning new things all the time," Whitacre said. "Like all medicine, we don't understand everything. The risk of not protecting children with vaccines is much worse. The number one thing that adds 25 to 30 years to your life span is vaccines."