Marie Hansen of Spanish Fork says something changed the day she took her son Dylan to his 1-year-old doctor's appointment.

Until then, Dylan had been successfully overcoming developmental problems caused by his low birth weight. But when he got his MMR and chicken pox immunization shots, he started crying uncontrollably and stopped breathing regularly. Doctors and nurses were eventually able to stabilize him, but Hansen says she never learned exactly what happened. She assumes it was a seizure, but all she really knows is that she soon realized something was wrong.

"He just seemed really off the next week," Hansen said. "He didn't really run a fever or anything, he was just off. The best way I can describe it is that he kind of lost the spark in his eye. I can show you pictures and it's just night and day."

Hansen is among a small but growing number of parents who choose not to vaccinate their children, and according to the medical community, consequently increase the population's risk of disease. Arguments against vaccines include the idea that large pharmaceutical companies that manufacture the vaccines are corrupt and lobby for vaccine laws just to make money. There has also been increased interest in natural health and the idea that you can be healthy without medicines. But the biggest complaint is that vaccines are administered by force.

Laws in every state require school-aged children to receive a series of vaccine shots. Because there is overwhelming medical evidence and opinion stating that vaccines are not only safe but the greatest triumph of public health in history, many who choose not to vaccinate do so quietly and don't speak out about it for fear of being seen as a bad parent.

At 7 years old, Dylan is still non-verbal despite early intervention programs and thousands of dollars in therapy. Hansen said she never noticed any previous reaction to Dylan's or her other children's vaccinations. Dylan probably would have experienced various delays no matter what, she said, but she can't shake the idea that something changed that day. The experience scared her so bad she says none of her children will receive another vaccine, if she can help it.

Once home to one of the lowest vaccination rates in the nation, Utah has increased its rates in recent years, and now ranks 25th. But more parents are now signing exemption forms to avoid the required series of vaccine shots for their school-aged children. According to Dr. Joseph Miner, director of the Utah County Health Department, about 5 percent of Utah County children have vaccination exemptions with UCHD, a number that has been rising in recent years.

"Utah has a history of having some of the lowest immunization rates in the nation," Miner said. "We've been last, then next to last, then almost average, but we've never been above average."

Most other states have lower vaccine exemption rates, perhaps in part because Utah is among a minority of states that allow parents to cite medical, religious or philosophical objections to the immunizations. In other words, parents can opt out for any reason. Most states only allow medical or religious exemptions (requiring parents to state that vaccinations are against their religious beliefs) and Mississippi and West Virginia allow children to miss vaccinations only for medical reasons.

Immunization programs are becoming victims of their own success, Miner said, because as contagious diseases disappear, parents see less of a need to vaccinate their children. A recent Associated Press study found a rise in religious exemptions in states that don't allow philosophical exemptions. Some parents admitted their real concerns were about the safety of the vaccines, not their religious beliefs.

The increasing exemptions are a problem for everyone, because vaccines are only effective to the extent that everyone gets them. Dr. Russell J. Osguthorpe, a pediatric infectious disease specialist at Utah Valley Regional Medical Center in Provo, likens it to requiring everyone to drive the speed limit so everyone has a safe ride.

"We don't immunize just for fun, or because we can," Osguthorpe said. "It's because children die from preventable diseases."

A 2000 study of Colorado children found that those who filed religious or philosophical exemptions were 22 times more likely to acquire measles and six times more likely to acquire pertussis (whooping cough) than vaccinated children. Two years ago, Utah Valley saw an outbreak of whooping cough -- the county health department recorded more than seven times the normal amount of cases. Those sick kids can spread disease even to vaccinated children.

"Vaccines are between 95 and 99 percent effective," Miner said. "You've got anywhere from 1 to 5 percent of kids who for some reason have lost immunity or haven't developed it. That's a small percentage, but if you have 25 percent of other kids not immunized, then illness can spread through the whole population."

That's why Miner says deciding not to immunize your children puts them and their peers at risk. With 95 percent of the population in Utah Valley immune, there is little risk of an epidemic. But if that percentage continues growing, the risk would increase, and Miner said the state would have to disallow exemptions to protect the population.

Robert Johnston, an associate professor of history at the University of Illinois-Chicago, has studied the anti-vaccination movement for 20 years and said most of the resistance revolves around the freedom of making an informed choice.

"This is really the only area of American medical life that they're not allowed to offer a truly free consent," Johnston said. "Some of them may even vaccinate, but they may speak out for the right to choose. They're willing to hear that vaccines are safe, but they want to make that freedom of choice."

Interestingly, mandatory vaccination is one of the rare laws in society that citizens can choose not to follow. No one can declare themselves exempt from the speed limit, for example. So it's a push for freedom of choice in an area of public policy where adherence is already optional.

Why make a law and then allow people to break it? First, because here in the U.S., people value personal freedoms and rights so highly. Also, Brigham Young University public policy specialist Sven Wilson said the law sets an expectation of society, and even if it is optional, it encourages people to follow a particular path. Even an optional law has a greater influence than guidelines.

But vaccine skeptics say parents should do their homework before taking their children down the shot path.

"When you make a decision that involves a risk, you want to be the best parent and have the best information possible," said Barbara Loe Fisher, president of the National Vaccine Information Center, a leading vaccine skeptic group. "Vaccines should not be separated from the informed consent ethic in medicine. We recommend that parents do their homework and talk to one or more health professionals and get all the information they can."

Because following immunization law in Utah is optional given the exemptions, public officials are looking for other ways to encourage parents to immunize their children.

In Utah County, the Women, Infants and Children program has considered a plan to tie WIC food vouchers to vaccine records. Under the proposed plan, a parent whose child is up on his or her immunizations could receive three months of vouchers at a time, while parents of children who are not caught up would have to return to the WIC office each month. WIC officials support the plan, but the cost of keeping a nurse on hand to verify immunization records has been deemed prohibitive.

It's precisely the overwhelming medical and public support for vaccines that vaccine skeptic Fisher says drives some parents to hide their choice.

"You have people telling you you're unpatriotic and selfish when you're just trying to protect your child," Fisher said. "Parents who do not vaccinate their children are seen as selfish, and they're talked about as a danger to public health. And when they use a religious exemption to get out of it, they're called liars. So the problem is that when parents talk about this they can then be targeted by their communities."

Driving those who choose not to vaccinate underground is not the goal of public health officials like Utah County's Dr. Miner. He said his work is a constant effort to educate.

"You have to constantly educate people about what it used to be like with infant mortality and preventable diseases," Miner said. "But unfortunately it takes an outbreak of whooping cough to remind people that this is what our grandparents were talking about when you used to have six or 10 kids in order to raise four of them to adulthood. Now we take it for granted that we'll raise all of them to adulthood, but that's not the way it used to be."

Osguthorpe said his work has introduced him to many cases of children afflicted with one of the 27 vaccine-preventable diseases. He speaks of them as tragedies, but tragedies that could have been averted with a timely vaccination.

"I'm confused by people who don't vaccinate their kids," Osguthorpe said. "They're playing dice with their kid, if you look at the chances. As I see cases of preventable diseases, and I talk with the moms and dads, when I tell them that it was preventable, they're just so sad and wish it could be so different. I'd like to see people avoid some of the heartache that is avoidable."

Yes, vaccines have risks -- no medical treatment is 100 percent safe. Osguthorpe points out that, for all the good they do, vaccines aren't risk free.

In recent years, the number of reports to the CDC's national adverse event reporting system, which was created to catch problems with vaccines, has exceeded the reports of childhood diseases that are preventable by vaccines, with the exception of chickenpox, according to the Centers for Disease Control and Prevention's Manual for the Surveillance of Vaccine-Preventable Diseases printed in 2002. The manual concludes that "in the absence of disease, benefits of vaccination may be overshadowed by reports of vaccine adverse events," which could result in the resurgence of diseases that can be prevented by vaccines.

The National Immunization Program lists 27 diseases that are preventable by vaccines. Information from the CDC says nearly all those vaccines can lead to swelling or redness at the injection site and anything from mild to severe allergic reactions.

But medical evidence shows the more severe reactions to vaccines to be very rare. The CDC's site says seizures (jerking or staring) like the one that may have affected Dylan Hansen of Spanish Fork occur in 1 out of every 3,000 doses. But long-term problems like Dylan's mom describes, such as lowered consciousness and brain damage, occur in less than 1 out of a million cases.

"From an entire population point of view, the risk is so small that it is far, far outweighed by the benefits," Osguthorpe said. "But if you have had a bad reaction, even if it was one in a million, it was your child."

The CDC estimates that more than 1 in 10,000 people die each year from causes related to influenza, which is preventable by a vaccine. The CDC also estimates that more than 1 in 10,000 people each year will get whooping cough, also preventable by vaccination.

It's not inconceivable that a vaccine could result in a severe reaction that causes the death of the patient, but such cases are so rare that a causal link is difficult to establish.

A rotavirus vaccine was taken off the market in 1999 because it raised some red flags in the adverse event reporting system. It was linked to an increased risk for intussusception, a type of bowel obstruction, in young infants. As soon as the cases showed up, Osguthorpe said, the vaccine was pulled and reviewed. It was later replaced by a more effective vaccine.

Doctors should report cases like Hansen's, but they may not always link the problem to the vaccine because they are so rare. Osguthorpe said if there were any kind of trend developing, as was the case with intussusception, it would certainly be noticed and corrected.

Autism accusation

Like Hansen, Springville resident Sondra Hurst says her child, Sara, was harmed by a vaccine. Within hours of the shot, Sara came down with a high fever and wouldn't eat or drink regularly. She quit walking and talking and was soon diagnosed with autism. Despite medical evidence to the contrary, Hurst doesn't doubt the vaccination contributed to her child's problems.

"I felt strongly that it was night and day," Hurst said. "She was a healthy child, we had no reason to be worried, and within a matter of 24 to 48 hours, she was having all these problems. So for me there was no question."

Sara's older brother also has autism. Hurst said there is probably a genetic disposition for the condition in her family, but believes the vaccine could have triggered the problem.

As more study as been done on the condition, autism can now be diagnosed in early childhood, and Osguthorpe said that timing could coincide with a child's vaccination. Even though the two events can happen around the same time, there's no evidence that vaccines cause autism.

Another oft-cited safety concern is the use of mercury-containing thimerosal as a preservative in vaccines. Despite studies showing thimerosal had no adverse side effects, the preservative hasn't been used in any vaccines for six years.

To deal with claims of vaccine injury or death, the Vaccine Immunization Compensation Program was established in 1988. A group of attorneys judge complaints and have decided to award settlements in only about 2,300 cases since the program's inception. Hansen said she has not filed a claim because she didn't feel like fighting for a settlement.

Claims filed with the program have increased since 2001, coinciding with a rise in diagnoses of autism. Many parents link the disorder to a vaccination their child received, despite overwhelming medical evidence showing no link between vaccines and neurological disorders, including autism and many others.

Besides the risks associated with vaccines, some parents complain that there are just too many shots. The complete schedule of childhood immunizations recommended by the National Immunization Program requires 15 vaccine doses. Some of the doses can be combined and given in a single shot, but others can only be given separately and still others require "boosters" later in life. It could add up to a dozen or more needle pokes.

"I'm not totally against vaccinations," Hurst said. "But I think the way they have them scheduled is too much. There should be an option to split them up. I just think it's safer that way."

The schedule is there for a reason, Osguthorpe said. First, as a public health program, it was developed for everyone, not for individuals. Second, it was developed based on the times children are vulnerable to each disease.

"The reason we immunize babies is that's when they need to become immune," Osguthorpe said. "You and I don't die from pertussis but babies do. And we don't give the measles, mumps and rubella vaccine to children under 1 year because those diseases don't affect younger children."

Still, Hansen is with Hurst in believing that there shouldn't be a single vaccine schedule. She believes her child's pre-existing condition should have elicited special care.

"Doctors really, I feel, need to wake up to the point that all kids are different," Hansen said. "It shouldn't be a cookie-cutter approach. I think they need to look at the children and their health issues. Obviously I don't have any research to back it up, but in my opinion, there's a reason some kids are having problems with the vaccines."

Margie Golden, director of school nursing at the UCHD, said many times parents who file exemptions end up vaccinating their children later, either because colleges require them (most don't accept exemptions), for travel or to serve a mission for the LDS Church. Though the children are eventually immunized, Golden says they were at unnecessary risk for years.

"The diseases hit the younger kids too, and maybe more so, so immunizing the younger kids is important too," Golden said. "We encourage parents to keep their kids up to date from birth on. I do hate to hear of cases of pertussis or other diseases that are preventable with a vaccine."

This is not the first time in Utah's history that there has been resistance to vaccines. An outbreak of smallpox in the late 1890s triggered a statewide vaccine controversy that lasted many years.

At the time, it had been more than 100 years since Edward Jenner first discovered a smallpox vaccine, but vaccination was not required in Utah. More than three years before the turn of the century, Utah saw 3,000 cases of smallpox and 26 deaths from the disease. Neighboring states, which by then had much success with the smallpox vaccine, complained that Utah was spreading the disease to the rest of the Intermountain West.

The state health commissioner, Theodore B. Beatty, enacted a mandatory vaccination ordinance. Even in the face of an epidemic, there was immediate, statewide opposition to the measure. The state Legislature passed a bill to repeal the mandatory vaccination requirement, and the governor quickly vetoed it. The Legislature just as swiftly overturned his veto and vaccination wasn't required in Utah until many years later.

Some of the backlash can be explained by a prevailing sentiment that The Church of Jesus Christ of Latter-day Saints was opposed to vaccinations. This was not the case, as is demonstrated by a May 1900 statement from church president Lorenzo Snow urging members to get vaccinated.

But an editor at the church-owned Deseret News frequently spoke out against vaccines, saying they were worse than the disease itself. Despite the president's statement, anti-vaccine sentiment held a firm position in Utah for decades.

By the 1930s, smallpox cases in Utah had significantly decreased, but there were still more cases than elsewhere. States that had mandatory vaccination laws in place weren't seeing any cases at all. Now the disease has been all but eradicated. The same goes for polio -- there have been no cases of the crippling ailment in the United States since 1979.

"The success of these vaccines is huge," Osguthorpe said. "They're one of the greatest success stories of our time."