School vaccine exemptions put kids at risk

A nurse prepares to administer a flu vaccine in Cambridge, Massachusetts December 12, 2003. Rules that allow parents to exempt their children from immunization requirements for ''philosophical'' reasons are putting all kids at risk of outbreaks of vaccine-preventable disease, Arkansas researchers warn.

NEW YORK (Reuters Health) - Rules that allow parents to exempt their children from immunization requirements for "philosophical" reasons are putting all kids at risk of outbreaks of vaccine-preventable disease, Arkansas researchers warn.

Since 2003, when the state began allowing these exemptions from school vaccine rules, rising numbers of children have been going without immunization, Dr. Joseph W. Thompson of the Arkansas Center for Health Improvement in Little Rock and colleagues found.

Arkansas had previously allowed exemption from vaccine requirements for religious or medical reasons, but parents had to belong to a "recognized religion that included tenets against immunization" for the exemption to be allowed, Thompson and colleagues explain in the American Journal of Preventive Medicine.

Parents challenged the law, and a federal court ruled that requiring a religion to be "recognized" was not constitutional. Arkansas now allows religious, philosophical and medical exemptions, which must be renewed annually.

Since the change, Thompson and his team found, the number of exemptions requested by parents has steadily risen, while the percentage of exemptions that are non-medical has made up an increasingly large portion of the total.

For example, in 2001 (when the philosophical exemption was not available) there were 419 religious exemptions and 110 medical exemptions statewide. In 2004-2005, there were 721 philosophical exemptions, 362 religious exemptions, and 62 medical exemptions.

And in the 10 districts with the highest exemption rates, none were medical.

In order for vaccines to be effective, Thompson noted, they must provide an individual with immunity, and they must also provide "herd" immunity by covering a certain percentage of people in the community, estimated to be at least 93 percent for measles, for example.

"Concentrations of children who are not immunized could result in a loss of community-level immunity and ultimately erode public health protection against vaccine-preventable illness," the researchers warn.

"Nationwide we're seeing parents increasingly undervalue the protection that vaccines give because the diseases they have never seen," Thompson said. "When polio affected a child in every school, the polio vaccine was rapidly adopted."

According to Thompson, policymakers and medical professionals need to do a better job of informing parents about the risks and benefits of vaccines. "Just throwing information at them without putting it in the context of what their concerns are probably is not going to be very valuable."

SOURCE: American Journal of Preventive Medicine, March 2007.