Elena Neil's oldest daughter already showed symptoms of autism by the time Neil learned that Pennsylvania allowed parents to claim a religious exemption from mandatory vaccinations of their children.

Fever and rashes afflicted Gina, now 9, each time she received a vaccination, her mother said. But when Gina became reclusive and introverted after five vaccinations in one day when she was about 15 months old, Neil wondered if those treatments were causing her daughter's health problems.

Several years of naturopathic treatments have rid Gina of her neurological disorder symptoms, her mother said. Yet she is allergic to penicillin, peanuts, wheat and gluten and has asthma. Neil said she believes the vaccinations caused those maladies.

"People look at me like I'm crazy because I've never had Olivia vaccinated," Neil, 40, of Bethel Park said about her second daughter, who is 5. "But she's had nothing of what Gina has."

Many parents believe vaccinations against diseases such as measles, diphtheria, mumps and chicken pox pose a danger to children because the serums contain ingredients such as mercury and aluminum. More Pennsylvania parents are choosing not to vaccinate their children.

The number of students in Pennsylvania claiming religious or medical exemptions from vaccinations has more than doubled in the past eight years -- to 24,919 last year from 9,722 in 1999, according to the state Department of Health.

Jeanne Truschel, 37, a speech pathologist who lives in Friendship, said her daughter Calla, 3, has never had a vaccination.

"I was really alarmed to learn about how many vaccines infants get in the first 24 months of their lives," Truschel said. "I didn't want her to be exposed to all those toxins. And she's completely healthy. She's never even had a runny nose."

'Diseases ... a plane ride away'


Doctors and public health officials counter that this attitude is unfounded, immoral and potentially catastrophic.

"It's unconscionable not to vaccinate your kids," said Dr. Toni Darville, chief of infectious diseases at Children's Hospital of Pittsburgh. "You have to have the moral grounding so you not only protect your child, but others as well. Especially with plane travel universal. Any of the serious infectious diseases are essentially a plane ride away."

Darville said some diseases -- such as whooping cough in England and Japan and mumps in New York and Iowa -- have reappeared because of falling vaccination rates.

"As diseases go away, people aren't aware of how horrible it can be, so there's no impetus to say, 'Oh my God,' " Darville said. "All these diseases can cause severe symptoms and even death."

Link to autism studied


Dr. Samuel Stebbins, professor and researcher with the University of Pittsburgh's Center for Vaccine Research, called vaccines "the single most effective public health intervention available" but said he supports "parents' right and responsibility to question the 'system' and to make informed choices."

At the start of the 20th century, a third of deaths in the United States were from infectious diseases, Stebbins said. The average life expectancy for those born in 1900 was 47.3, according to the Centers for Disease Control and Prevention in Atlanta.

By 2004, life expectancy had reached 77.8. Citing other CDC data, Stebbins said cases and deaths from diseases such as smallpox, polio and measles have plummeted during the past 100 years.

Yet Stebbins concedes his mind remains open about the causes for the mushrooming rate of autism in American children, though he believes the causes likely are environmental toxins and genetic susceptibility. In 1987, the autism rate was one in 10,000, reported journalist David Kirby in his book, "Evidence of Harm," which investigated the link between autism and mercury in vaccines. The book was honored in 2005 for outstanding investigative reporting by the nonprofit organization Investigative Reporters and Editors.

A CDC study published in February said about one child in 150 develops autism or a related disorder by the age of 8.

Federal public health officials recommended -- but did not ban -- phasing out the use of thimerosal, a mercury preservative, in vaccines in the late 1990s. CDC spokesman Curtis Allen said officials made that decision based on "an abundance of caution," and all vaccines except those for flu have been mercury-free since 2002. The mercury preservative allows easier storage by enabling the production of multi-dose vaccine vials, Allen said. People can request thimerosal-free flu shots.

CDC and U.S. Food and Drug Administration officials point to studies that show no connection between mercury and autism.

But Dr. Mark Geier, 59, a private practitioner who has worked for the National Institutes of Health, and his son, David Geier, 27, of Silver Spring, Md., said that after conducting more than 25 independent studies, they believe there is a relationship between mercury and autism.

The Geiers published a paper last year in the peer-reviewed journal Neuroendocrinology Letters that examined side effects in patients who collectively received about 100 million doses of vaccines between 1994 and 2000.

They found "significant risks of autism, speech disorders, mental retardation, personality disorders, thinking abnormalities, ataxia, and neurodevelopmental delays in general were associated with mercury exposure from thimerosal-containing childhood vaccines." Ataxia is an unsteadiness and lack of coordination, generally caused by a brain disease.

'Not just the vaccine'


Dr. Sherri Tenpenny of Cleveland, a specialist in emergency medicine and osteopathic manipulation who has researched vaccinations, unapologetically opposes all vaccinations because of more than 100 toxins beyond mercury -- such as aluminum and polysorbate 80 -- that can be found in vaccines. Tenpenny argues the benefits of vaccines are outweighed by the neurological disorders and other illnesses caused by the frequency of vaccinations and the accumulation of the toxins they contain.

"When you look at the fact that we're the most highly vaccinated population in the world, yet we are sickest, in dollars spent, something is wrong with public health in this country," Tenpenny said. "I believe it's morally wrong to compel someone against their will to inject their children with substances that have potential to kill them."

Julie Hudak, 39, of Squirrel Hill owns a business that provides occupational, speech and other therapies to 26 children a week who have developmental disabilities including autism. Hudak has three children, 20 months, 4 and 6. All have received the traditional course of vaccinations. None has any neurological disorders.

"I believe in vaccines because the risk of epidemics breaking out because of people not getting them is scary," Hudak said.

She acknowledged, however, that children who are genetically predisposed to conditions such as autism and who suffer from environmental toxins could "be pushed over the edge" after receiving a certain vaccine.

"It's not just the vaccine that causes autism," she said.