Washington, USA - In public health circles they are known as "exempters" -- parents who for reasons of faith or philosophy choose not to immunize their children against diseases such as measles and whooping cough. Some exempters claim that childhood vaccines contain unnatural or harmful ingredients; others say they regard vaccination as a "dark force" that conflicts with their belief in a benevolent deity; still others are members of a religion that bars invasive procedures.
Regardless of the reason, the ranks of parents exercising nonmedical exemptions to vaccination are growing, public health officials say. Although the number remains small and involves an estimated 2 to 3 percent of the approximately 3 million children who start kindergarten annually, the trend alarms some experts. They worry that parents' fears are being stoked by misinformation about vaccines that abounds on the Internet and are using religion as an excuse to opt out of immunization. This refusal, scientists say, threatens a cornerstone of public health.
"People are motivated by their fears," said Paul Offit, chief of the division of infectious diseases at Children's Hospital of Philadelphia and one of the most outspoken defenders of vaccines. "Young mothers today don't see these diseases, they didn't grow up with them. Vaccines were not a hard sell" several decades ago, when people saw children killed by measles, brain-damaged from haemophilus influenzae or deaf after a case of mumps.
"I think religious exemptions are used as a default," said Offit, a professor of pediatrics at the University of Pennsylvania who has written several books on vaccines.
Half a dozen studies, Offit noted, have found no link between vaccines and autism, one of the major objections cited by those who spurn immunization. The overwhelming consensus among scientists, he said, is that the benefits of vaccination greatly outweigh the risks.
But that view is rejected by such anti-immunization groups as Vaccine Liberation and Citizens for Vaccine Choice. They claim the shots are harmful and urge parents to exercise their right to avoid them.
Two weeks ago, a Northern Virginia-based group called the National Vaccine Information Center launched a campaign calling for "broad exemptions for medical, religious and conscientious belief reasons." According to Barbara Loe Fisher, the group's co-founder, "forcing vaccination is a violation of human rights."
Every state and the District grants medical exemptions to children who are allergic to components of vaccines or whose immune systems are too compromised to benefit from them. And all but two states -- West Virginia and Mississippi -- allow parents to opt out on religious grounds.
In some states, such as Maryland, parents need only sign a form claiming a religious exemption, while parents in Virginia and the District must submit a notarized statement.
In recent years lawmakers in 21 states, none of them local, have created "personal-belief" or philosophical exemptions that permit children to skip vaccines on the grounds that they conflict with a parent's views.
"Many states are making personal-belief exemptions easier," said Saad B. Omer, a vaccine researcher at the Johns Hopkins Bloomberg School of Public Health. "Filing for an exemption should at least be a function of conviction, not laziness."
In 2006, Omer and other vaccine researchers published a study in the Journal of the American Medical Association which examined rates of pertussis, or whooping cough, in states with personal-belief exemptions and those where nonmedical exemptions were easy to obtain.
They found that the incidence of the disease was about 50 percent higher in states with personal-belief exemptions than those without them and in jurisdictions where religious exemptions were easy to obtain than in those with more stringent requirements.
Researchers also found a substantial increase in personal-belief exemptions: the rate grew from 0.99 percent in 1999 in states that allow them to 2.5 percent in 2004.
In Maryland, state statistics show that 1,300 kindergarteners, or 0.2 percent, were exempted on religious grounds in 2004, a rate that rose to 0.5 percent, or 2,500 children, in 2006.
Parents who decide not to immunize, Omer noted, are making decisions for children other than their own. No shot confers 100 percent immunity, and unvaccinated children can spread disease to those who are too young or too medically fragile to be immunized, including those suffering from cancer.
Currently, Omer noted, a measles epidemic is unfolding in San Diego, where 64 cases of the disease have been reported. All but one of the affected children, he said, had not been vaccinated, some because they were too young for the shot, which is administered at about 12 months.
A bill that would grant personal-belief exemptions has been introduced in New York, where Rita Palma and her husband have been battling school officials over a religious exemption for the youngest of her three sons. Palma, a Roman Catholic, said that in 2006, after several years of receiving signs from God, she decided not to take her son for the last of three required hepatitis B shots.
"Vaccinations," Palma said in an interview, "are based on a very dark, threatening pessimistic principle" that if you do not inject your child, he will become sick or could die. "To me, good health is earned through seeking God."
After a two-hour meeting informally known as a "sincerity interview" -- attended by the Palmas, their lawyer and an attorney for the Bayport-Blue Point School District on Long Island -- school officials rejected the couple's request for a religious exemption. In a February 2007 letter they cited the couple's history of immunizing their children.
Palma ultimately took her son for the shot so he could attend school but has appealed the decision to the New York State Supreme Court.
"I'm furious about it," she said. "This is an absolute injustice."
Fisher, of the vaccine information center, said she claimed a religious exemption to certain shots required in the District and later in Virginia for her daughter when she attended parochial schools.
Fisher said her older son had a bad reaction to a childhood vaccine, and "I was very afraid that I would have another child this would happen to," though her pediatrician recommended the girl be immunized.
"I prayed about whether God wanted me to do what this physician wanted me to do," she recalled. After a three-hour meeting, she said, her Lutheran pastor signed a statement in support of her exemption. "He said he didn't have to agree with me but that I had a sincere religious belief." School officials accepted it, she said.
Although she is aware that some parents might manufacture religious objections, Fisher said she doesn't recommend it. "If you are going to take a religious exemption, you have to have a sincere belief and be true to the spirit and intent of religious exemption," she said.
Maryland officials say they are watching immunization trends. Ed Hirshhorn, chief of the state's Vaccines for Children program, said that although he thinks the religious exemption requirement is "too easy," officials are reluctant to seek stronger requirements in the absence of an outbreak of disease or dramatic increase in parental refusal.
"You're always opening Pandora's box," he said.